diff --git a/pydoctor/model.py b/pydoctor/model.py
index b89b78e4d..52bb77f53 100644
--- a/pydoctor/model.py
+++ b/pydoctor/model.py
@@ -9,7 +9,6 @@
 
 import abc
 import ast
-from functools import partial
 from itertools import chain
 from collections import defaultdict
 import datetime
diff --git a/pydoctor/mro.py b/pydoctor/mro.py
index db63a86bf..30997712f 100644
--- a/pydoctor/mro.py
+++ b/pydoctor/mro.py
@@ -27,7 +27,7 @@
 
 from collections import deque
 from itertools import islice
-from typing import Callable, List, Tuple, Optional, TypeVar
+from typing import List, Tuple, Optional, TypeVar
 
 T = TypeVar('T')
 
diff --git a/pydoctor/test/test_mro.py b/pydoctor/test/test_mro.py
index ac221a088..17b910e55 100644
--- a/pydoctor/test/test_mro.py
+++ b/pydoctor/test/test_mro.py
@@ -1,5 +1,4 @@
 from typing import List, Optional, Type
-import pytest
 
 from pydoctor import model, stanutils
 from pydoctor.templatewriter import pages, util
diff --git a/pydoctor/topsort.py b/pydoctor/topsort.py
index 0f59f6760..729a4868e 100644
--- a/pydoctor/topsort.py
+++ b/pydoctor/topsort.py
@@ -8,7 +8,7 @@
     from typing import TypeAlias
 
 T = TypeVar('T')
-Graph = TypeAlias = dict[T, list[T]]
+Graph: TypeAlias = dict[T, list[T]]
 
 if sys.version_info >= (3, 9):
     from graphlib import TopologicalSorter, CycleError
@@ -113,7 +113,7 @@ def prepare(self):
             # nodes as possible before cycles block more progress
             cycle = self._find_cycle()
             if cycle:
-                raise CycleError(f"nodes are in a cycle", cycle)
+                raise CycleError("nodes are in a cycle", cycle)
 
         def get_ready(self):
             """Return a tuple of all the nodes that are ready.