diff --git a/qutebrowser/commands/parsers.py b/qutebrowser/commands/parsers.py
index 163bdddb7..3c8471afa 100644
--- a/qutebrowser/commands/parsers.py
+++ b/qutebrowser/commands/parsers.py
@@ -120,7 +120,7 @@ class CommandParser:
 
     """
 
-    def __init__(self, parent=None):
+    def __init__(self):
         self._cmd = None
         self._args = []
 
diff --git a/qutebrowser/models/settingcompletion.py b/qutebrowser/models/settingcompletion.py
index 1f182a146..5724c941b 100644
--- a/qutebrowser/models/settingcompletion.py
+++ b/qutebrowser/models/settingcompletion.py
@@ -31,7 +31,7 @@ class SettingSectionCompletionModel(CompletionModel):
         super().__init__(parent)
         cat = self.new_category("Config sections")
         for name in configdata().keys():
-            self.new_item(cat, name )
+            self.new_item(cat, name)
 
 
 class SettingOptionCompletionModel(CompletionModel):
diff --git a/run_checks.py b/run_checks.py
index cefba8757..2eb2f2392 100644
--- a/run_checks.py
+++ b/run_checks.py
@@ -66,6 +66,7 @@ options = {
         ],
         'flake8': [
             'E241',  # Multiple spaces after ,
+            'E265',  # Block comment should start with '#'
         ],
         'pep257': [
             'D102',  # Docstring missing, will be handled by others