diff --git a/.flake8 b/.flake8
index ac29a9eaa307..48d7a27eada5 100644
--- a/.flake8
+++ b/.flake8
@@ -4,7 +4,6 @@ exclude =
     # These paths should be triaged and either fixed or moved to the list below.
     devtools/shared,
     dom/bindings,
-    gfx/tests,
     ipc/ipdl/ipdl,
     layout/base/tests/marionette,
     layout/reftests/border-image,
diff --git a/dom/bindings/Configuration.py b/dom/bindings/Configuration.py
index c1eb524b407f..0cf5170506ce 100644
--- a/dom/bindings/Configuration.py
+++ b/dom/bindings/Configuration.py
@@ -286,27 +286,60 @@ class Configuration(DescriptorProvider):
                 curr = self.descriptorsByFile.get(val, [])
                 continue
             elif key == "hasInterfaceObject":
-                getter = lambda x: x.interface.hasInterfaceObject()
+
+                def getter(x):
+                    return x.interface.hasInterfaceObject()
+
             elif key == "hasInterfacePrototypeObject":
-                getter = lambda x: x.interface.hasInterfacePrototypeObject()
+
+                def getter(x):
+                    return x.interface.hasInterfacePrototypeObject()
+
             elif key == "hasInterfaceOrInterfacePrototypeObject":
-                getter = lambda x: x.hasInterfaceOrInterfacePrototypeObject()
+
+                def getter(x):
+                    return x.hasInterfaceOrInterfacePrototypeObject()
+
             elif key == "isCallback":
-                getter = lambda x: x.interface.isCallback()
+
+                def getter(x):
+                    return x.interface.isCallback()
+
             elif key == "isJSImplemented":
-                getter = lambda x: x.interface.isJSImplemented()
+
+                def getter(x):
+                    return x.interface.isJSImplemented()
+
             elif key == "isExposedInAnyWorker":
-                getter = lambda x: x.interface.isExposedInAnyWorker()
+
+                def getter(x):
+                    return x.interface.isExposedInAnyWorker()
+
             elif key == "isExposedInWorkerDebugger":
-                getter = lambda x: x.interface.isExposedInWorkerDebugger()
+
+                def getter(x):
+                    return x.interface.isExposedInWorkerDebugger()
+
             elif key == "isExposedInAnyWorklet":
-                getter = lambda x: x.interface.isExposedInAnyWorklet()
+
+                def getter(x):
+                    return x.interface.isExposedInAnyWorklet()
+
             elif key == "isExposedInWindow":
-                getter = lambda x: x.interface.isExposedInWindow()
+
+                def getter(x):
+                    return x.interface.isExposedInWindow()
+
             elif key == "isExposedInShadowRealms":
-                getter = lambda x: x.interface.isExposedInShadowRealms()
+
+                def getter(x):
+                    return x.interface.isExposedInShadowRealms()
+
             elif key == "isSerializable":
-                getter = lambda x: x.interface.isSerializable()
+
+                def getter(x):
+                    return x.interface.isSerializable()
+
             else:
                 # Have to watch out: just closing over "key" is not enough,
                 # since we're about to mutate its value
diff --git a/dom/bindings/parser/tests/test_union.py b/dom/bindings/parser/tests/test_union.py
index 8a7948daf6b9..7fc1236d54e3 100644
--- a/dom/bindings/parser/tests/test_union.py
+++ b/dom/bindings/parser/tests/test_union.py
@@ -3,6 +3,8 @@ import itertools
 import string
 
 # We'd like to use itertools.chain but it's 2.6 or higher.
+
+
 def chain(*iterables):
     # chain('ABC', 'DEF') --> A B C D E F
     for it in iterables: