diff --git a/aider/commands.py b/aider/commands.py
index dad0de4f5..27268deb9 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -86,7 +86,10 @@ class Commands:
             return
 
         if self.coder.repo.is_dirty():
-            self.io.tool_error("The repository has uncommitted changes. Please commit or stash them before undoing.")
+            self.io.tool_error(
+                "The repository has uncommitted changes. Please commit or stash them before"
+                " undoing."
+            )
             return
 
         local_head = self.coder.repo.git.rev_parse("HEAD")
@@ -100,7 +103,10 @@ class Commands:
                 self.io.tool_error(f"Error: Unable to get the remote 'origin/{current_branch}'.")
                 return
             if local_head == remote_head:
-                self.io.tool_error("The last commit has already been pushed to the origin. Undoing is not possible.")
+                self.io.tool_error(
+                    "The last commit has already been pushed to the origin. Undoing is not"
+                    " possible."
+                )
                 return
 
         last_commit = self.coder.repo.head.commit
diff --git a/aider/dump.py b/aider/dump.py
index 060ad28b3..de6dcbb6d 100644
--- a/aider/dump.py
+++ b/aider/dump.py
@@ -1,27 +1,29 @@
 import traceback
 import json
 
+
 def cvt(s):
     if isinstance(s, str):
         return s
     try:
-        return json.dumps(s, indent = 4)
+        return json.dumps(s, indent=4)
     except TypeError:
         return str(s)
 
+
 def dump(*vals):
     # http://docs.python.org/library/traceback.html
-    stack= traceback.extract_stack()
-    vars= stack[-2][3]
+    stack = traceback.extract_stack()
+    vars = stack[-2][3]
 
     # strip away the call to dump()
-    vars= '('.join(vars.split('(')[1:])
-    vars= ')'.join(vars.split(')')[:-1])
+    vars = "(".join(vars.split("(")[1:])
+    vars = ")".join(vars.split(")")[:-1])
 
-    vals= [cvt(v) for v in vals]
-    has_newline = sum(1 for v in vals if '\n' in v)
+    vals = [cvt(v) for v in vals]
+    has_newline = sum(1 for v in vals if "\n" in v)
     if has_newline:
-        print('%s:' % vars)
-        print(', '.join(vals))
+        print("%s:" % vars)
+        print(", ".join(vals))
     else:
-        print('%s:' % vars, ', '.join(vals))
+        print("%s:" % vars, ", ".join(vals))
diff --git a/aider/utils.py b/aider/utils.py
index 0b10f838a..1b9873b4b 100644
--- a/aider/utils.py
+++ b/aider/utils.py
@@ -51,7 +51,9 @@ def try_dotdotdots(whole, part, replace):
             continue
 
         if whole.count(part) != 1:
-            raise ValueError("No perfect matching chunk in edit block with ... or part appears more than once")
+            raise ValueError(
+                "No perfect matching chunk in edit block with ... or part appears more than once"
+            )
 
         whole = whole.replace(part, replace, 1)
 
diff --git a/tests/test_main.py b/tests/test_main.py
index 39baf0f56..e1d56d2fb 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -13,14 +13,14 @@ class TestMain(TestCase):
     def test_main_with_empty_dir_no_files_on_command(self):
         with tempfile.TemporaryDirectory() as temp_dir:
             os.chdir(temp_dir)
-            pipe_input = create_input(StringIO(''))
+            pipe_input = create_input(StringIO(""))
             main([], input=pipe_input, output=DummyOutput())
             pipe_input.close()
 
     def test_main_with_empty_dir_new_file(self):
         with tempfile.TemporaryDirectory() as temp_dir:
             os.chdir(temp_dir)
-            pipe_input = create_input(StringIO(''))
+            pipe_input = create_input(StringIO(""))
             main(["foo.txt"], input=pipe_input, output=DummyOutput())
             pipe_input.close()
             self.assertTrue(os.path.exists("foo.txt"))
@@ -29,7 +29,7 @@ class TestMain(TestCase):
         with tempfile.TemporaryDirectory() as temp_dir:
             os.chdir(temp_dir)
             subprocess.run(["git", "init"], cwd=temp_dir)
-            pipe_input = create_input(StringIO(''))
+            pipe_input = create_input(StringIO(""))
             main(["--yes", "foo.txt"], input=pipe_input, output=DummyOutput())
             pipe_input.close()
             self.assertTrue(os.path.exists("foo.txt"))