diff --git a/homeassistant/components/automation/numeric_state.py b/homeassistant/components/automation/numeric_state.py
index ab3529235d6..115f351a4f9 100644
--- a/homeassistant/components/automation/numeric_state.py
+++ b/homeassistant/components/automation/numeric_state.py
@@ -82,7 +82,7 @@ def _in_range(value, range_start, range_end):
     try:
         value = float(value)
     except ValueError:
-        _LOGGER.warn("Missing value in numeric check")
+        _LOGGER.warning("Missing value in numeric check")
         return False
 
     if range_start is not None and range_end is not None:
diff --git a/homeassistant/components/automation/zone.py b/homeassistant/components/automation/zone.py
index 4bf7eccf41e..f0f800bd313 100644
--- a/homeassistant/components/automation/zone.py
+++ b/homeassistant/components/automation/zone.py
@@ -46,6 +46,7 @@ def trigger(hass, config, action):
         from_match = _in_zone(hass, zone_entity_id, from_s) if from_s else None
         to_match = _in_zone(hass, zone_entity_id, to_s)
 
+        # pylint: disable=too-many-boolean-expressions
         if event == EVENT_ENTER and not from_match and to_match or \
            event == EVENT_LEAVE and from_match and not to_match:
             action()
diff --git a/homeassistant/components/binary_sensor/arest.py b/homeassistant/components/binary_sensor/arest.py
index 3077fe40bdb..7eafca9f2ae 100644
--- a/homeassistant/components/binary_sensor/arest.py
+++ b/homeassistant/components/binary_sensor/arest.py
@@ -6,9 +6,10 @@ The arest sensor will consume an exposed aREST API of a device.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/binary_sensor.arest/
 """
-import logging
-import requests
 from datetime import timedelta
+import logging
+
+import requests
 
 from homeassistant.util import Throttle
 from homeassistant.components.binary_sensor import BinarySensorDevice
diff --git a/homeassistant/components/camera/__init__.py b/homeassistant/components/camera/__init__.py
index 169c97595af..fc5c739c888 100644
--- a/homeassistant/components/camera/__init__.py
+++ b/homeassistant/components/camera/__init__.py
@@ -7,19 +7,20 @@ Component to interface with various cameras.
 For more details about this component, please refer to the documentation at
 https://home-assistant.io/components/camera/
 """
-import requests
 import logging
-import time
 import re
+import time
+
+import requests
+
 from homeassistant.helpers.entity import Entity
+from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.const import (
     ATTR_ENTITY_PICTURE,
     HTTP_NOT_FOUND,
     ATTR_ENTITY_ID,
     )
 
-from homeassistant.helpers.entity_component import EntityComponent
-
 
 DOMAIN = 'camera'
 DEPENDENCIES = ['http']
diff --git a/homeassistant/components/camera/foscam.py b/homeassistant/components/camera/foscam.py
index d4d707c790f..b210e1a2f1b 100644
--- a/homeassistant/components/camera/foscam.py
+++ b/homeassistant/components/camera/foscam.py
@@ -7,11 +7,12 @@ For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/camera.foscam/
 """
 import logging
-from homeassistant.helpers import validate_config
-from homeassistant.components.camera import DOMAIN
-from homeassistant.components.camera import Camera
+
 import requests
 
+from homeassistant.helpers import validate_config
+from homeassistant.components.camera import DOMAIN, Camera
+
 _LOGGER = logging.getLogger(__name__)
 
 
diff --git a/homeassistant/components/camera/generic.py b/homeassistant/components/camera/generic.py
index 7e9542908d5..c81febccc86 100644
--- a/homeassistant/components/camera/generic.py
+++ b/homeassistant/components/camera/generic.py
@@ -7,11 +7,12 @@ For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/camera.generic/
 """
 import logging
-from requests.auth import HTTPBasicAuth
-from homeassistant.helpers import validate_config
-from homeassistant.components.camera import DOMAIN
-from homeassistant.components.camera import Camera
+
 import requests
+from requests.auth import HTTPBasicAuth
+
+from homeassistant.helpers import validate_config
+from homeassistant.components.camera import DOMAIN, Camera
 
 _LOGGER = logging.getLogger(__name__)
 
diff --git a/homeassistant/components/camera/mjpeg.py b/homeassistant/components/camera/mjpeg.py
index 1e643304add..0d59c8d60c7 100644
--- a/homeassistant/components/camera/mjpeg.py
+++ b/homeassistant/components/camera/mjpeg.py
@@ -6,13 +6,14 @@ Support for IP Cameras.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/camera.mjpeg/
 """
-import logging
-from requests.auth import HTTPBasicAuth
-from homeassistant.helpers import validate_config
-from homeassistant.components.camera import DOMAIN
-from homeassistant.components.camera import Camera
-import requests
 from contextlib import closing
+import logging
+
+import requests
+from requests.auth import HTTPBasicAuth
+
+from homeassistant.helpers import validate_config
+from homeassistant.components.camera import DOMAIN, Camera
 
 _LOGGER = logging.getLogger(__name__)
 
diff --git a/homeassistant/components/ecobee.py b/homeassistant/components/ecobee.py
index a41bf7f25cc..03a678f5c49 100644
--- a/homeassistant/components/ecobee.py
+++ b/homeassistant/components/ecobee.py
@@ -26,14 +26,15 @@ ecobee:
 
 """
 
+from datetime import timedelta
+import logging
+import os
+
 from homeassistant.loader import get_component
 from homeassistant import bootstrap
 from homeassistant.util import Throttle
 from homeassistant.const import (
     EVENT_PLATFORM_DISCOVERED, ATTR_SERVICE, ATTR_DISCOVERED, CONF_API_KEY)
-from datetime import timedelta
-import logging
-import os
 
 DOMAIN = "ecobee"
 DISCOVER_THERMOSTAT = "ecobee.thermostat"
diff --git a/homeassistant/components/light/zwave.py b/homeassistant/components/light/zwave.py
index 31cd64d2530..02664ed896c 100644
--- a/homeassistant/components/light/zwave.py
+++ b/homeassistant/components/light/zwave.py
@@ -6,12 +6,13 @@ Support for Z-Wave lights.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/light.zwave/
 """
+# Because we do not compile openzwave on CI
 # pylint: disable=import-error
-import homeassistant.components.zwave as zwave
+from threading import Timer
 
 from homeassistant.const import STATE_ON, STATE_OFF
 from homeassistant.components.light import (Light, ATTR_BRIGHTNESS)
-from threading import Timer
+import homeassistant.components.zwave as zwave
 
 
 def setup_platform(hass, config, add_devices, discovery_info=None):
diff --git a/homeassistant/components/media_player/firetv.py b/homeassistant/components/media_player/firetv.py
index 1b2c921e3d4..e5f9885f86e 100644
--- a/homeassistant/components/media_player/firetv.py
+++ b/homeassistant/components/media_player/firetv.py
@@ -49,7 +49,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
             _LOGGER.info(
                 'Device %s accessible and ready for control', device_id)
         else:
-            _LOGGER.warn(
+            _LOGGER.warning(
                 'Device %s is not registered with firetv-server', device_id)
     except requests.exceptions.RequestException:
         _LOGGER.error('Could not connect to firetv-server at %s', host)
diff --git a/homeassistant/components/media_player/itunes.py b/homeassistant/components/media_player/itunes.py
index 275e7d96dee..5d08a7e95d4 100644
--- a/homeassistant/components/media_player/itunes.py
+++ b/homeassistant/components/media_player/itunes.py
@@ -8,6 +8,8 @@ https://home-assistant.io/components/media_player.itunes/
 """
 import logging
 
+import requests
+
 from homeassistant.components.media_player import (
     MediaPlayerDevice, MEDIA_TYPE_MUSIC, MEDIA_TYPE_PLAYLIST, SUPPORT_PAUSE,
     SUPPORT_SEEK, SUPPORT_VOLUME_SET, SUPPORT_VOLUME_MUTE,
@@ -17,8 +19,6 @@ from homeassistant.components.media_player import (
 from homeassistant.const import (
     STATE_IDLE, STATE_PLAYING, STATE_PAUSED, STATE_OFF, STATE_ON)
 
-import requests
-
 _LOGGER = logging.getLogger(__name__)
 
 SUPPORT_ITUNES = SUPPORT_PAUSE | SUPPORT_VOLUME_SET | SUPPORT_VOLUME_MUTE | \
diff --git a/homeassistant/components/media_player/kodi.py b/homeassistant/components/media_player/kodi.py
index eda143b6cce..6fe6be554c6 100644
--- a/homeassistant/components/media_player/kodi.py
+++ b/homeassistant/components/media_player/kodi.py
@@ -15,11 +15,6 @@ from homeassistant.components.media_player import (
 from homeassistant.const import (
     STATE_IDLE, STATE_PLAYING, STATE_PAUSED, STATE_OFF)
 
-try:
-    import jsonrpc_requests
-except ImportError:
-    jsonrpc_requests = None
-
 _LOGGER = logging.getLogger(__name__)
 REQUIREMENTS = ['jsonrpc-requests==0.1']
 
@@ -31,11 +26,6 @@ SUPPORT_KODI = SUPPORT_PAUSE | SUPPORT_VOLUME_SET | SUPPORT_VOLUME_MUTE | \
 def setup_platform(hass, config, add_devices, discovery_info=None):
     """ Sets up the kodi platform. """
 
-    global jsonrpc_requests    # pylint: disable=invalid-name
-    if jsonrpc_requests is None:
-        import jsonrpc_requests as jsonrpc_requests_
-        jsonrpc_requests = jsonrpc_requests_
-
     add_devices([
         KodiDevice(
             config.get('name', 'Kodi'),
@@ -60,6 +50,7 @@ class KodiDevice(MediaPlayerDevice):
     # pylint: disable=too-many-public-methods
 
     def __init__(self, name, url, auth=None):
+        import jsonrpc_requests
         self._name = name
         self._url = url
         self._server = jsonrpc_requests.Server(url, auth=auth)
@@ -77,6 +68,7 @@ class KodiDevice(MediaPlayerDevice):
 
     def _get_players(self):
         """ Returns the active player objects or None """
+        import jsonrpc_requests
         try:
             return self._server.Player.GetActivePlayers()
         except jsonrpc_requests.jsonrpc.TransportError:
diff --git a/homeassistant/components/notify/xmpp.py b/homeassistant/components/notify/xmpp.py
index 016e0a949fd..4b688fb7a79 100644
--- a/homeassistant/components/notify/xmpp.py
+++ b/homeassistant/components/notify/xmpp.py
@@ -8,14 +8,14 @@ https://home-assistant.io/components/notify.xmpp/
 """
 import logging
 
-_LOGGER = logging.getLogger(__name__)
-
 from homeassistant.helpers import validate_config
 from homeassistant.components.notify import (
     DOMAIN, ATTR_TITLE, BaseNotificationService)
 
 REQUIREMENTS = ['sleekxmpp==1.3.1', 'dnspython3==1.12.0']
 
+_LOGGER = logging.getLogger(__name__)
+
 
 def get_service(hass, config):
     """ Get the Jabber (XMPP) notification service. """
diff --git a/homeassistant/components/recorder.py b/homeassistant/components/recorder.py
index acda166e12a..126d8c9f40e 100644
--- a/homeassistant/components/recorder.py
+++ b/homeassistant/components/recorder.py
@@ -73,7 +73,7 @@ def row_to_state(row):
 def row_to_event(row):
     """ Convert a databse row to an event. """
     try:
-        return Event(row[1], json.loads(row[2]), EventOrigin[row[3].lower()],
+        return Event(row[1], json.loads(row[2]), EventOrigin(row[3]),
                      date_util.utc_from_timestamp(row[5]))
     except ValueError:
         # When json.loads fails
diff --git a/homeassistant/components/script.py b/homeassistant/components/script.py
index f8240bbf7f5..bf7c51fe3fb 100644
--- a/homeassistant/components/script.py
+++ b/homeassistant/components/script.py
@@ -9,7 +9,6 @@ https://home-assistant.io/components/script/
 """
 import logging
 from datetime import timedelta
-import homeassistant.util.dt as date_util
 from itertools import islice
 import threading
 
@@ -17,6 +16,7 @@ from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.helpers.entity import ToggleEntity
 from homeassistant.helpers.event import track_point_in_utc_time
 from homeassistant.util import slugify, split_entity_id
+import homeassistant.util.dt as date_util
 from homeassistant.const import (
     ATTR_ENTITY_ID, EVENT_TIME_CHANGED, STATE_ON, SERVICE_TURN_ON,
     SERVICE_TURN_OFF)
@@ -73,12 +73,12 @@ def setup(hass, config):
 
     for object_id, cfg in config[DOMAIN].items():
         if object_id != slugify(object_id):
-            _LOGGER.warn("Found invalid key for script: %s. Use %s instead.",
-                         object_id, slugify(object_id))
+            _LOGGER.warning("Found invalid key for script: %s. Use %s instead",
+                            object_id, slugify(object_id))
             continue
         if not isinstance(cfg.get(CONF_SEQUENCE), list):
-            _LOGGER.warn("Key 'sequence' for script %s should be a list",
-                         object_id)
+            _LOGGER.warning("Key 'sequence' for script %s should be a list",
+                            object_id)
             continue
         alias = cfg.get(CONF_ALIAS, object_id)
         script = Script(hass, object_id, alias, cfg[CONF_SEQUENCE])
diff --git a/homeassistant/components/sensor/arest.py b/homeassistant/components/sensor/arest.py
index 332725102dd..f1faa7cc932 100644
--- a/homeassistant/components/sensor/arest.py
+++ b/homeassistant/components/sensor/arest.py
@@ -6,13 +6,14 @@ The arest sensor will consume an exposed aREST API of a device.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.arest/
 """
-import logging
-import requests
 from datetime import timedelta
+import logging
+
+import requests
 
-from homeassistant.util import Throttle
-from homeassistant.helpers.entity import Entity
 from homeassistant.const import DEVICE_DEFAULT_NAME
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import Throttle
 
 _LOGGER = logging.getLogger(__name__)
 
diff --git a/homeassistant/components/sensor/ecobee.py b/homeassistant/components/sensor/ecobee.py
index a6499949015..5950b5deccb 100644
--- a/homeassistant/components/sensor/ecobee.py
+++ b/homeassistant/components/sensor/ecobee.py
@@ -25,10 +25,11 @@ ecobee:
   hold_temp: True
 
 """
+import logging
+
 from homeassistant.helpers.entity import Entity
 from homeassistant.components import ecobee
 from homeassistant.const import TEMP_FAHRENHEIT
-import logging
 
 DEPENDENCIES = ['ecobee']
 
diff --git a/homeassistant/components/sensor/forecast.py b/homeassistant/components/sensor/forecast.py
index aa3dd3d3d04..c024c19b5f7 100644
--- a/homeassistant/components/sensor/forecast.py
+++ b/homeassistant/components/sensor/forecast.py
@@ -9,17 +9,11 @@ https://home-assistant.io/components/sensor.forecast/
 import logging
 from datetime import timedelta
 
-REQUIREMENTS = ['python-forecastio==1.3.3']
-
-try:
-    import forecastio
-except ImportError:
-    forecastio = None
-
 from homeassistant.util import Throttle
 from homeassistant.const import (CONF_API_KEY, TEMP_CELCIUS)
 from homeassistant.helpers.entity import Entity
 
+REQUIREMENTS = ['python-forecastio==1.3.3']
 _LOGGER = logging.getLogger(__name__)
 
 # Sensor types are defined like so:
@@ -53,11 +47,7 @@ MIN_TIME_BETWEEN_UPDATES = timedelta(seconds=120)
 
 def setup_platform(hass, config, add_devices, discovery_info=None):
     """ Get the Forecast.io sensor. """
-
-    global forecastio  # pylint: disable=invalid-name
-    if forecastio is None:
-        import forecastio as forecastio_
-        forecastio = forecastio_
+    import forecastio
 
     if None in (hass.config.latitude, hass.config.longitude):
         _LOGGER.error("Latitude or longitude not set in Home Assistant config")
@@ -141,6 +131,7 @@ class ForeCastSensor(Entity):
     # pylint: disable=too-many-branches
     def update(self):
         """ Gets the latest data from Forecast.io and updates the states. """
+        import forecastio
 
         self.forecast_client.update()
         data = self.forecast_client.data
@@ -209,6 +200,7 @@ class ForeCastData(object):
     @Throttle(MIN_TIME_BETWEEN_UPDATES)
     def update(self):
         """ Gets the latest data from Forecast.io. """
+        import forecastio
 
         forecast = forecastio.load_forecast(self._api_key,
                                             self.latitude,
diff --git a/homeassistant/components/sensor/glances.py b/homeassistant/components/sensor/glances.py
index 092e4c75733..7938ae7e659 100644
--- a/homeassistant/components/sensor/glances.py
+++ b/homeassistant/components/sensor/glances.py
@@ -6,9 +6,10 @@ Gathers system information of hosts which running glances.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.glances/
 """
-import logging
-import requests
 from datetime import timedelta
+import logging
+
+import requests
 
 from homeassistant.util import Throttle
 from homeassistant.helpers.entity import Entity
diff --git a/homeassistant/components/sensor/rest.py b/homeassistant/components/sensor/rest.py
index 7fe3a583b08..53609dbb237 100644
--- a/homeassistant/components/sensor/rest.py
+++ b/homeassistant/components/sensor/rest.py
@@ -6,10 +6,11 @@ The rest sensor will consume JSON responses sent by an exposed REST API.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.rest/
 """
-import logging
-import requests
-from json import loads
 from datetime import timedelta
+from json import loads
+import logging
+
+import requests
 
 from homeassistant.util import Throttle
 from homeassistant.helpers.entity import Entity
diff --git a/homeassistant/components/sensor/rpi_gpio.py b/homeassistant/components/sensor/rpi_gpio.py
index 2e2746fe9d4..ef7ea8c33c1 100644
--- a/homeassistant/components/sensor/rpi_gpio.py
+++ b/homeassistant/components/sensor/rpi_gpio.py
@@ -6,13 +6,10 @@ Allows to configure a binary state sensor using RPi GPIO.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.rpi_gpio/
 """
+# pylint: disable=import-error
 import logging
 from homeassistant.helpers.entity import Entity
 
-try:
-    import RPi.GPIO as GPIO
-except ImportError:
-    GPIO = None
 from homeassistant.const import (DEVICE_DEFAULT_NAME,
                                  EVENT_HOMEASSISTANT_START,
                                  EVENT_HOMEASSISTANT_STOP)
@@ -29,10 +26,7 @@ _LOGGER = logging.getLogger(__name__)
 # pylint: disable=unused-argument
 def setup_platform(hass, config, add_devices, discovery_info=None):
     """ Sets up the Raspberry PI GPIO ports. """
-    if GPIO is None:
-        _LOGGER.error('RPi.GPIO not available. rpi_gpio ports ignored.')
-        return
-    # pylint: disable=no-member
+    import RPi.GPIO as GPIO
     GPIO.setmode(GPIO.BCM)
 
     sensors = []
@@ -65,6 +59,7 @@ class RPiGPIOSensor(Entity):
     def __init__(self, port_name, port_num, pull_mode,
                  value_high, value_low, bouncetime):
         # pylint: disable=no-member
+        import RPi.GPIO as GPIO
         self._name = port_name or DEVICE_DEFAULT_NAME
         self._port = port_num
         self._pull = GPIO.PUD_DOWN if pull_mode == "DOWN" else GPIO.PUD_UP
diff --git a/homeassistant/components/sensor/sabnzbd.py b/homeassistant/components/sensor/sabnzbd.py
index e478daac2f9..98d76a302dd 100644
--- a/homeassistant/components/sensor/sabnzbd.py
+++ b/homeassistant/components/sensor/sabnzbd.py
@@ -6,12 +6,11 @@ Monitors SABnzbd NZB client API.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.sabnzbd/
 """
-from homeassistant.util import Throttle
 from datetime import timedelta
+import logging
 
 from homeassistant.helpers.entity import Entity
-
-import logging
+from homeassistant.util import Throttle
 
 REQUIREMENTS = ['https://github.com/jamespcole/home-assistant-nzb-clients/'
                 'archive/616cad59154092599278661af17e2a9f2cf5e2a9.zip'
diff --git a/homeassistant/components/sensor/transmission.py b/homeassistant/components/sensor/transmission.py
index 484b045f295..62afdd39bf4 100644
--- a/homeassistant/components/sensor/transmission.py
+++ b/homeassistant/components/sensor/transmission.py
@@ -6,14 +6,13 @@ Monitors Transmission BitTorrent client API.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.transmission/
 """
-from homeassistant.util import Throttle
 from datetime import timedelta
-from homeassistant.const import CONF_HOST, CONF_USERNAME, CONF_PASSWORD
-
-from homeassistant.helpers.entity import Entity
-
 import logging
 
+from homeassistant.const import CONF_HOST, CONF_USERNAME, CONF_PASSWORD
+from homeassistant.util import Throttle
+from homeassistant.helpers.entity import Entity
+
 REQUIREMENTS = ['transmissionrpc==0.11']
 SENSOR_TYPES = {
     'current_status': ['Status', ''],
diff --git a/homeassistant/components/sensor/vera.py b/homeassistant/components/sensor/vera.py
index 1848c680517..7fb72fd91b7 100644
--- a/homeassistant/components/sensor/vera.py
+++ b/homeassistant/components/sensor/vera.py
@@ -95,7 +95,7 @@ class VeraSensor(Entity):
 
     @property
     def state_attributes(self):
-        attr = super().state_attributes
+        attr = {}
         if self.vera_device.has_battery:
             attr[ATTR_BATTERY_LEVEL] = self.vera_device.battery_level + '%'
 
diff --git a/homeassistant/components/sensor/zwave.py b/homeassistant/components/sensor/zwave.py
index 23d2f8948f8..1ed831b286d 100644
--- a/homeassistant/components/sensor/zwave.py
+++ b/homeassistant/components/sensor/zwave.py
@@ -6,9 +6,11 @@ Interfaces with Z-Wave sensors.
 For more details about this platform, please refer to the documentation
 at https://home-assistant.io/components/zwave/
 """
+# Because we do not compile openzwave on CI
 # pylint: disable=import-error
-from homeassistant.helpers.event import track_point_in_time
 import datetime
+
+from homeassistant.helpers.event import track_point_in_time
 import homeassistant.util.dt as dt_util
 import homeassistant.components.zwave as zwave
 from homeassistant.helpers.entity import Entity
diff --git a/homeassistant/components/switch/hikvisioncam.py b/homeassistant/components/switch/hikvisioncam.py
index 2d91acdf361..c85aae4a7f0 100644
--- a/homeassistant/components/switch/hikvisioncam.py
+++ b/homeassistant/components/switch/hikvisioncam.py
@@ -6,11 +6,12 @@ Support turning on/off motion detection on Hikvision cameras.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/switch.hikvision/
 """
-from homeassistant.helpers.entity import ToggleEntity
-from homeassistant.const import STATE_ON, STATE_OFF
-from homeassistant.const import CONF_HOST, CONF_USERNAME, CONF_PASSWORD
 import logging
 
+from homeassistant.helpers.entity import ToggleEntity
+from homeassistant.const import (STATE_ON, STATE_OFF,
+                                 CONF_HOST, CONF_USERNAME, CONF_PASSWORD)
+
 _LOGGING = logging.getLogger(__name__)
 REQUIREMENTS = ['hikvision==0.4']
 # pylint: disable=too-many-arguments
diff --git a/homeassistant/components/switch/mystrom.py b/homeassistant/components/switch/mystrom.py
index 36a62fe33e4..919ff28e4ef 100644
--- a/homeassistant/components/switch/mystrom.py
+++ b/homeassistant/components/switch/mystrom.py
@@ -91,12 +91,9 @@ class MyStromSwitch(SwitchDevice):
         try:
             request = requests.get('{}/report'.format(self._resource),
                                    timeout=10)
-            if request.json()['relay'] is True:
-                self._state = True
-            else:
-                self._state = False
-
-            self.consumption = request.json()['power']
+            data = request.json()
+            self._state = bool(data['relay'])
+            self.consumption = data['power']
         except requests.exceptions.ConnectionError:
             _LOGGER.error("No route to device '%s'. Is device offline?",
                           self._resource)
diff --git a/homeassistant/components/switch/transmission.py b/homeassistant/components/switch/transmission.py
index f3f6a9a8765..1f0da4a00e0 100644
--- a/homeassistant/components/switch/transmission.py
+++ b/homeassistant/components/switch/transmission.py
@@ -6,12 +6,12 @@ Enable or disable Transmission BitTorrent client Turtle Mode.
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/switch.transmission/
 """
-from homeassistant.const import CONF_HOST, CONF_USERNAME, CONF_PASSWORD
-from homeassistant.const import STATE_ON, STATE_OFF
-
-from homeassistant.helpers.entity import ToggleEntity
 import logging
 
+from homeassistant.const import (CONF_HOST, CONF_USERNAME, CONF_PASSWORD,
+                                 STATE_ON, STATE_OFF)
+from homeassistant.helpers.entity import ToggleEntity
+
 _LOGGING = logging.getLogger(__name__)
 REQUIREMENTS = ['transmissionrpc==0.11']
 
diff --git a/homeassistant/components/switch/zwave.py b/homeassistant/components/switch/zwave.py
index 493e2234bcf..f4777340445 100644
--- a/homeassistant/components/switch/zwave.py
+++ b/homeassistant/components/switch/zwave.py
@@ -4,8 +4,8 @@ homeassistant.components.switch.zwave
 
 Zwave platform that handles simple binary switches.
 """
+# Because we do not compile openzwave on CI
 # pylint: disable=import-error
-
 import homeassistant.components.zwave as zwave
 
 from homeassistant.components.switch import SwitchDevice
diff --git a/homeassistant/components/thermostat/ecobee.py b/homeassistant/components/thermostat/ecobee.py
index 78f4d555c9c..66117954a51 100644
--- a/homeassistant/components/thermostat/ecobee.py
+++ b/homeassistant/components/thermostat/ecobee.py
@@ -25,11 +25,12 @@ ecobee:
   hold_temp: True
 
 """
+import logging
+
+from homeassistant.components import ecobee
 from homeassistant.components.thermostat import (ThermostatDevice, STATE_COOL,
                                                  STATE_IDLE, STATE_HEAT)
 from homeassistant.const import (TEMP_FAHRENHEIT, STATE_ON, STATE_OFF)
-from homeassistant.components import ecobee
-import logging
 
 DEPENDENCIES = ['ecobee']
 
diff --git a/homeassistant/components/updater.py b/homeassistant/components/updater.py
index a020a6c0abb..d4eb97f5ec5 100644
--- a/homeassistant/components/updater.py
+++ b/homeassistant/components/updater.py
@@ -47,10 +47,10 @@ def get_newest_version():
         return req.json()['info']['version']
     except requests.RequestException:
         _LOGGER.exception('Could not contact PyPI to check for updates')
-        return
+        return None
     except ValueError:
         _LOGGER.exception('Received invalid response from PyPI')
-        return
+        return None
     except KeyError:
         _LOGGER.exception('Response from PyPI did not include version')
-        return
+        return None
diff --git a/homeassistant/config.py b/homeassistant/config.py
index 2c2152df7a0..3d17fce5e17 100644
--- a/homeassistant/config.py
+++ b/homeassistant/config.py
@@ -67,7 +67,7 @@ def create_default_config(config_dir, detect_location=True):
         Returns path to new config file if success, None if failed. """
     config_path = os.path.join(config_dir, YAML_CONFIG_FILE)
 
-    info = {attr: default for attr, default, *_ in DEFAULT_CONFIG}
+    info = {attr: default for attr, default, _, _ in DEFAULT_CONFIG}
 
     location_info = detect_location and loc_util.detect_location_info()
 
diff --git a/homeassistant/helpers/event.py b/homeassistant/helpers/event.py
index 60377fd1f5d..3934a6c52ef 100644
--- a/homeassistant/helpers/event.py
+++ b/homeassistant/helpers/event.py
@@ -124,6 +124,7 @@ def track_utc_time_change(hass, action, year=None, month=None, day=None,
 
         mat = _matcher
 
+        # pylint: disable=too-many-boolean-expressions
         if mat(now.year, year) and \
            mat(now.month, month) and \
            mat(now.day, day) and \
diff --git a/homeassistant/util/package.py b/homeassistant/util/package.py
index fdfbc133944..fd320090736 100644
--- a/homeassistant/util/package.py
+++ b/homeassistant/util/package.py
@@ -1,12 +1,13 @@
 """Helpers to install PyPi packages."""
 import logging
 import os
-import pkg_resources
 import subprocess
 import sys
 import threading
 from urllib.parse import urlparse
 
+import pkg_resources
+
 _LOGGER = logging.getLogger(__name__)
 INSTALL_LOCK = threading.Lock()
 
@@ -27,7 +28,7 @@ def install_package(package, upgrade=True, target=None):
             args += ['--target', os.path.abspath(target)]
 
         try:
-            return 0 == subprocess.call(args)
+            return subprocess.call(args) == 0
         except subprocess.SubprocessError:
             _LOGGER.exception('Unable to install pacakge %s', package)
             return False
@@ -50,4 +51,5 @@ def check_package_exists(package, lib_dir):
             return True
 
     # Check packages from global + virtual environment
+    # pylint: disable=not-an-iterable
     return any(dist in req for dist in pkg_resources.working_set)
diff --git a/pylintrc b/pylintrc
index e8455cf4245..768cd3d46ff 100644
--- a/pylintrc
+++ b/pylintrc
@@ -9,6 +9,7 @@ reports=no
 # abstract-class-not-used - is flaky, should not show up but does
 # unused-argument - generic callbacks and setup methods create a lot of warnings
 # global-statement - used for the on-demand requirement installation
+# redefined-variable-type - this is Python, we're duck typing!
 disable=
   locally-disabled,
   duplicate-code,
@@ -16,7 +17,8 @@ disable=
   abstract-class-little-used,
   abstract-class-not-used,
   unused-argument,
-  global-statement
+  global-statement,
+  redefined-variable-type
 
 [EXCEPTIONS]
 overgeneral-exceptions=Exception,HomeAssistantError
diff --git a/requirements_all.txt b/requirements_all.txt
index bf07dd4dfcf..01af666b720 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -170,4 +170,3 @@ https://github.com/persandstrom/python-verisure/archive/9873c4527f01b1ba1f72ae60
 
 # homeassistant.components.zwave
 pydispatcher==2.0.5
-
diff --git a/script/gen_requirements_all.py b/script/gen_requirements_all.py
index b10c0f38ed8..730886075ec 100755
--- a/script/gen_requirements_all.py
+++ b/script/gen_requirements_all.py
@@ -16,6 +16,7 @@ COMMENT_REQUIREMENTS = [
 
 
 def explore_module(package, explore_children):
+    """ Explore the modules. """
     module = importlib.import_module(package)
 
     found = []
@@ -33,10 +34,10 @@ def explore_module(package, explore_children):
 
 
 def core_requirements():
+    """ Gather core requirements out of setup.py. """
     with open('setup.py') as inp:
         reqs_raw = re.search(
             r'REQUIRES = \[(.*?)\]', inp.read(), re.S).group(1)
-
     return re.findall(r"'(.*?)'", reqs_raw)
 
 
@@ -45,14 +46,13 @@ def comment_requirement(req):
     return any(ign in req for ign in COMMENT_REQUIREMENTS)
 
 
-def main():
-    if not os.path.isfile('requirements_all.txt'):
-        print('Run this from HA root dir')
-        return
-
+def gather_modules():
+    """ Collect the information and construct the output. """
     reqs = OrderedDict()
 
     errors = []
+    output = []
+
     for package in sorted(explore_module('homeassistant.components', True)):
         try:
             module = importlib.import_module(package)
@@ -69,22 +69,43 @@ def main():
     if errors:
         print("Found errors")
         print('\n'.join(errors))
-        return
-
-    print('# Home Assistant core')
-    print('\n'.join(core_requirements()))
-    print()
+        return None
 
+    output.append('# Home Assistant core')
+    output.append('\n')
+    output.append('\n'.join(core_requirements()))
+    output.append('\n')
     for pkg, requirements in reqs.items():
         for req in sorted(requirements,
                           key=lambda name: (len(name.split('.')), name)):
-            print('#', req)
+            output.append('\n# {}'.format(req))
 
         if comment_requirement(pkg):
-            print('#', pkg)
+            output.append('\n# {}\n'.format(pkg))
         else:
-            print(pkg)
-        print()
+            output.append('\n{}\n'.format(pkg))
+
+    return ''.join(output)
+
+
+def write_file(data):
+    """ Writes the modules to the requirements_all.txt. """
+    with open('requirements_all.txt', 'w+') as req_file:
+        req_file.write(data)
+
+
+def main():
+    """ Main """
+    if not os.path.isfile('requirements_all.txt'):
+        print('Run this from HA root dir')
+        return
+
+    data = gather_modules()
+
+    if data is None:
+        return
+
+    write_file(data)
 
 if __name__ == '__main__':
     main()