fixup: small typing related changes

mattermost_matchmaker/matchmaking.py

-import copy
 import random
-from typing import Generator, Iterable, Tuple, List
-import mattermost
+from typing import Generator, Iterable, Tuple, Optional, List
+import mattermost  # type: ignore
 
 #pylint: disable=invalid-name
 
@@ -11,7 +10,7 @@ def random_nonrepeating_tuples(population: Iterable, n: int) -> Generator[tuple,
     Generates a random sequence of n-tuples, using every element in population only once
     """
 
-    population_copy = copy.copy(population)
+    population_copy = list(population)
     random.shuffle(population_copy)
 
     buffer = list()
@@ -52,7 +51,7 @@ def matching_in_channel(client: mattermost.MMApi, channel_id: str,
         client.create_post(channel_id=channel_id, message=left_out_message.format(user=user_data))
 
 
-def create_group(client: mattermost.MMApi, ids: Iterable[str]) -> None:
+def create_group(client: mattermost.MMApi, ids: Iterable[str]) -> str:
     """
     Creating a group-message for the group
     """

mattermost_matchmaker/run.py

 #!/usr/bin/env python3
 import argparse
-import mattermost
+import mattermost  # type: ignore
 from mattermost_matchmaker.matchmaking import matching_in_channel
 
 #pylint: disable=too-many-arguments

mypy.ini

+[mypy]
+
+[mypy-mattermost.*]
+ignore_missing_imports = True
+
+[mypy-pylint.*]
+ignore_missing_imports = True
+