diff --git a/client/contributions.py b/client/contributions.py
index 175b004..b837978 100644
--- a/client/contributions.py
+++ b/client/contributions.py
@@ -25,7 +25,7 @@ def _user_score(self, user_id: str, start_date: datetime = None, end_date: datet
 
     @staticmethod
     def _filter_prs(prs: List[PullRequest], start_date: datetime = None, end_date: datetime = None) -> List[PullRequest]:
-        if start_date != None and end_date != None:
+        if start_date is not None and end_date is not None:
             return [pr for pr in prs if pr.created_between(start_date, end_date)]
         else:
             return prs
diff --git a/client/github_stats.py b/client/github_stats.py
index 3527342..f064737 100644
--- a/client/github_stats.py
+++ b/client/github_stats.py
@@ -23,10 +23,10 @@ def list_of_prs(self, user_id: str, state=None, request_parallelization_count=5)
         prs = Pool(request_parallelization_count).map(
             self._to_pull_request, items)
 
-        if state == None:
+        if state is None:
             return prs
         else:
-            def stateNotEqual(pr: PullRequest) -> Boolean:
+            def stateNotEqual(pr: PullRequest) -> bool:
                 return pr._state != state
 
             return filter(stateNotEqual, prs)
diff --git a/client_test/models/pr_test_data.py b/client_test/models/pr_test_data.py
index 7368d57..2b6155b 100644
--- a/client_test/models/pr_test_data.py
+++ b/client_test/models/pr_test_data.py
@@ -4,7 +4,7 @@
 
 class PRData:
     def __init__(self, data: dict = None):
-        if data == None:
+        if data is None:
             with open('./client_test/models/empty_pr_data.json') as file:
                 self.data = json.load(file)
         else:
@@ -17,7 +17,7 @@ def with_pr_url(self, url: str = 'some-url'):
 
     def with_label(self, label_to_add: str = None):
         data = copy.deepcopy(self.data)
-        if label_to_add == None:
+        if label_to_add is None:
             label_number = len(data["issues_data"]["labels"]) + 1
             label_to_add = f'label-{label_number}'
 
diff --git a/client_test/models/pull_request_test.py b/client_test/models/pull_request_test.py
index 273dfcd..3917c32 100644
--- a/client_test/models/pull_request_test.py
+++ b/client_test/models/pull_request_test.py
@@ -18,7 +18,7 @@ def test_should_create_pull_request():
         assert pr._created_at == datetime(2014, 4, 24, 16, 34, 47)
         assert pr._owner == 'owner_user_id'
         assert pr._pr_raised_by == 'pr_raised_by_user_id'
-        assert pr._merged == False
+        assert pr._merged is False
 
     @staticmethod
     def test_summary():
@@ -34,7 +34,7 @@ def test_should_not_be_spam_when_labels_do_not_contain_invalid_and_spam():
         data = _input.data
         pr = PullRequest(**data)
 
-        assert pr.is_spam() == False
+        assert pr.is_spam() is False
 
     @staticmethod
     def test_should_be_spam_when_labels_contain_invalid():
@@ -72,7 +72,7 @@ def test_not_in_between():
         assert pr.created_between(
             start_date=datetime(2020, 1, 1),
             end_date=datetime(2021, 1, 1)
-        ) == False
+        ) is False
 
     @staticmethod
     def test_created_at_start():
diff --git a/stats.py b/stats.py
index 0416e91..e7ef158 100644
--- a/stats.py
+++ b/stats.py
@@ -1,11 +1,8 @@
-import sys
 from argparse import ArgumentParser, ArgumentTypeError
 from datetime import datetime
-from typing import List
 
 from client.contributions import Contributions
 from client.github_stats import GithubStats
-from client.models.user_stats import UserStats
 
 
 def valid_date(s: str) -> datetime: