Stop using deprecated datetime methods.

nucypher/blockchain/eth/decorators.py

@@ -2,7 +2,7 @@
 
 import functools
 import inspect
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Callable, Optional, TypeVar, Union
 
 import eth_utils
@@ -111,7 +111,7 @@ def save_receipt(actor_method) -> Callable:  # TODO: rename to "save_result"?
     @functools.wraps(actor_method)
     def wrapped(self, *args, **kwargs) -> dict:
         receipt_or_txhash = actor_method(self, *args, **kwargs)
-        self._saved_receipts.append((datetime.utcnow(), receipt_or_txhash))
+        self._saved_receipts.append((datetime.now(timezone.utc), receipt_or_txhash))
         return receipt_or_txhash
     return wrapped
 

nucypher/crypto/tls.py

@@ -42,7 +42,7 @@ def generate_self_signed_certificate(
         private_key = ec.generate_private_key(curve(), default_backend())
     public_key = private_key.public_key()
 
-    now = datetime.datetime.utcnow()
+    now = datetime.datetime.now(datetime.timezone.utc)
     fields = [x509.NameAttribute(NameOID.COMMON_NAME, host)]
 
     subject = issuer = x509.Name(fields)

nucypher/utilities/events.py

@@ -188,7 +188,7 @@ class EventScanner:
             # minor chain reorganisation?
             return None
         last_time = block_info["timestamp"]
-        return datetime.datetime.utcfromtimestamp(last_time)
+        return datetime.datetime.fromtimestamp(last_time, tz=datetime.timezone.utc)
 
     def get_suggested_scan_start_block(self):
         """Get where we should start to scan for new token events.

tests/unit/test_event_scanner.py

@@ -1,6 +1,6 @@
 import math
 import time
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Tuple
 from unittest.mock import MagicMock, Mock
 
@@ -112,12 +112,14 @@ def test_get_block_timestamp():
 
     now = time.time()
     web3.eth.get_block.return_value = {"timestamp": now}
-    assert scanner.get_block_timestamp(block_num=0) == datetime.utcfromtimestamp(now)
+    assert scanner.get_block_timestamp(block_num=0) == datetime.fromtimestamp(
+        now, tz=timezone.utc
+    )
 
     other_time = time.time() - 1231231
     web3.eth.get_block.return_value = {"timestamp": other_time}
-    assert scanner.get_block_timestamp(block_num=21) == datetime.utcfromtimestamp(
-        other_time
+    assert scanner.get_block_timestamp(block_num=21) == datetime.fromtimestamp(
+        other_time, tz=timezone.utc
     )