diff --git a/TEST_APPS/testcases/example/test_cmdline.py b/TEST_APPS/testcases/example/test_cmdline.py
index d1dbcd7ea0..8796e13a7b 100644
--- a/TEST_APPS/testcases/example/test_cmdline.py
+++ b/TEST_APPS/testcases/example/test_cmdline.py
@@ -19,7 +19,7 @@ from icetea_lib.bench import Bench
 class Testcase(Bench):
     def __init__(self):
         self.device = None
-        Bench.__init__(self,
+        super(Testcase, self).__init__(self,
                        name="test_cmdline",
                        title="Smoke test for command line interface",
                        status="released",
diff --git a/TEST_APPS/testcases/netsocket/SOCKET_BIND_PORT.py b/TEST_APPS/testcases/netsocket/SOCKET_BIND_PORT.py
index 5149286205..eb166d4cae 100644
--- a/TEST_APPS/testcases/netsocket/SOCKET_BIND_PORT.py
+++ b/TEST_APPS/testcases/netsocket/SOCKET_BIND_PORT.py
@@ -25,7 +25,7 @@ class MultipleTestcase(Bench):
         }
 
         testcase_args.update(kwargs)
-        Bench.__init__(self, **testcase_args)
+        super(MultipleTestcase, self).__init__(self, **testcase_args)
 
     def setup(self):
         self.command("dut1", "ifup")
diff --git a/TEST_APPS/testcases/netsocket/TCPSERVER_ACCEPT.py b/TEST_APPS/testcases/netsocket/TCPSERVER_ACCEPT.py
index 55d6e6d50e..cf69b27002 100644
--- a/TEST_APPS/testcases/netsocket/TCPSERVER_ACCEPT.py
+++ b/TEST_APPS/testcases/netsocket/TCPSERVER_ACCEPT.py
@@ -3,13 +3,13 @@
 #
 from icetea_lib.bench import Bench
 from interface import interfaceUp, interfaceDown
-from icetea_lib.tools import test_case
 import threading
 import time
 
+
 class Testcase(Bench):
     def __init__(self):
-        Bench.__init__(self,
+        super(Testcase, self).__init__(self,
                        name="TCPSERVER_ACCEPT",
                        title = "TCPSERVER_ACCEPT",
                        purpose = "Test that TCPServer::bind(), TCPServer::listen() and TCPServer::accept() works",
diff --git a/TEST_APPS/testcases/netsocket/TCPSOCKET_ECHOTEST_BURST_SHORT.py b/TEST_APPS/testcases/netsocket/TCPSOCKET_ECHOTEST_BURST_SHORT.py
index d408a29320..8e142b67e0 100644
--- a/TEST_APPS/testcases/netsocket/TCPSOCKET_ECHOTEST_BURST_SHORT.py
+++ b/TEST_APPS/testcases/netsocket/TCPSOCKET_ECHOTEST_BURST_SHORT.py
@@ -2,14 +2,13 @@
 # Copyright (c) 2018, Arm Limited and affiliates.
 #
 from icetea_lib.bench import Bench, TestStepFail
-from icetea_lib.tools import test_case
 import random
 import string
 
 
 class Testcase(Bench):
     def __init__(self):
-        Bench.__init__(self,
+        super(Testcase, self).__init__(self,
                        name="TCPSOCKET_ECHOTEST_BURST_SHORT",
                        title="TCPSOCKET_ECHOTEST_BURST_SHORT",
                        purpose="Verify that TCPSocket can send burst of packets to echo server and read incoming packets",
diff --git a/requirements.txt b/requirements.txt
index ca3f57d3e0..0d4130656a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ IntelHex>=1.3
 junit-xml
 pyYAML
 requests
-mbed-ls>=0.2.13,<2.0
+mbed-ls>=1.4.2,==1.*
 mbed-host-tests>=1.1.2
 mbed-greentea>=0.2.24
 beautifulsoup4>=4
diff --git a/tools/test.py b/tools/test.py
index 27b2a86f00..57af4cf303 100644
--- a/tools/test.py
+++ b/tools/test.py
@@ -21,7 +21,6 @@ TEST BUILD
 from __future__ import print_function, division, absolute_import
 import sys
 import os
-import subprocess
 import fnmatch
 
 ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
diff --git a/tools/test_api.py b/tools/test_api.py
index 2fe0794976..fd2b4c760a 100644
--- a/tools/test_api.py
+++ b/tools/test_api.py
@@ -28,7 +28,6 @@ import pprint
 import random
 import argparse
 import datetime
-import errno
 import threading
 import ctypes
 import functools
diff --git a/tools/toolchains/__init__.py b/tools/toolchains/__init__.py
index 5b905d0e07..edf901bcab 100644
--- a/tools/toolchains/__init__.py
+++ b/tools/toolchains/__init__.py
@@ -1117,4 +1117,4 @@ TOOLCHAIN_CLASSES = {
     u'IAR': IAR
 }
 
-TOOLCHAINS = set(TOOLCHAIN_CLASSES.keys())
\ No newline at end of file
+TOOLCHAINS = set(TOOLCHAIN_CLASSES.keys())