diff --git a/test_time_to_merge.py b/test_time_to_merge.py
index abe5e86..08fa496 100644
--- a/test_time_to_merge.py
+++ b/test_time_to_merge.py
@@ -14,6 +14,7 @@
 
 from time_to_merge import measure_time_to_merge
 
+
 class TestMeasureTimeToMerge(unittest.TestCase):
     """Test suite for the measure_time_to_merge function."""
 
diff --git a/test_time_to_ready_for_review.py b/test_time_to_ready_for_review.py
index 16108ea..cd2b626 100644
--- a/test_time_to_ready_for_review.py
+++ b/test_time_to_ready_for_review.py
@@ -14,6 +14,7 @@
 
 from time_to_ready_for_review import get_time_to_ready_for_review
 
+
 class TestGetTimeToReadyForReview(unittest.TestCase):
     """Test suite for the get_time_to_ready_for_review function."""
 
@@ -33,11 +34,11 @@ def test_get_time_to_ready_for_review_event(self):
         pull_request = MagicMock()
         pull_request.draft = False
         event = MagicMock()
-        event.event = 'ready_for_review'
+        event.event = "ready_for_review"
         event.created_at = datetime.fromisoformat("2021-01-01T00:00:00Z")
         issue = MagicMock()
-        issue.issue.events.return_value=[event]
-        
+        issue.issue.events.return_value = [event]
+
         result = get_time_to_ready_for_review(issue, pull_request)
         expected_result = event.created_at
         self.assertEqual(result, expected_result)
@@ -47,10 +48,10 @@ def test_get_time_to_ready_for_review_no_event(self):
         pull_request = MagicMock()
         pull_request.draft = False
         event = MagicMock()
-        event.event = 'foobar'
+        event.event = "foobar"
         event.created_at = "2021-01-01T00:00:00Z"
         issue = MagicMock()
-        issue.events.return_value=[event]
+        issue.events.return_value = [event]
 
         result = get_time_to_ready_for_review(issue, pull_request)
         expected_result = None
diff --git a/time_to_merge.py b/time_to_merge.py
index dbf3d86..dbd4f2c 100644
--- a/time_to_merge.py
+++ b/time_to_merge.py
@@ -12,19 +12,19 @@
 
 """
 from datetime import datetime, timedelta
-from typing import List, Union
+from typing import Union
 
 import github3
 
+
 def measure_time_to_merge(
-    pull_request: github3.pulls.PullRequest,
-    ready_for_review_at: Union[datetime, None]
+    pull_request: github3.pulls.PullRequest, ready_for_review_at: Union[datetime, None]
 ) -> Union[timedelta, None]:
     """Measure the time it takes to merge a pull request.
 
     Args:
         pull_request (github3.pulls.PullRequest): A GitHub pull request.
-        ready_for_review_at (Union[timedelta, None]): When the PR was marked as ready for review 
+        ready_for_review_at (Union[timedelta, None]): When the PR was marked as ready for review
 
     Returns:
         Union[datetime.timedelta, None]: The time it takes to close the issue.
diff --git a/time_to_ready_for_review.py b/time_to_ready_for_review.py
index ea8aa26..8c744b1 100644
--- a/time_to_ready_for_review.py
+++ b/time_to_ready_for_review.py
@@ -19,13 +19,13 @@
 
 import github3
 
+
 def get_time_to_ready_for_review(
-    issue: github3.issues.Issue,
-    pull_request: github3.pulls.PullRequest
+    issue: github3.issues.Issue, pull_request: github3.pulls.PullRequest
 ) -> Union[datetime, None]:
     """If a pull request was formerly a draft, get the time it was marked as ready
     for review
-    
+
     Args:
         issue (github3.issues.Issue): A GitHub issue.
         pull_request (github3.pulls.PullRequest): A GitHub pull request.
@@ -38,7 +38,7 @@ def get_time_to_ready_for_review(
 
     events = issue.issue.events(number=50)
     for event in events:
-        if event.event == 'ready_for_review':
+        if event.event == "ready_for_review":
             return event.created_at
 
     return None