diff --git a/mox3/mox.py b/mox3/mox.py
index 85d4e0c..21e3535 100644
--- a/mox3/mox.py
+++ b/mox3/mox.py
@@ -911,8 +911,8 @@ class MethodSignatureChecker(object):
             raise ValueError('Could not get argument specification for %r'
                              % (method,))
         if (inspect.ismethod(method) or class_to_bind or (
-                hasattr(self, '_args') and len(self._args) > 0
-                and self._args[0] == 'self')):
+                hasattr(self, '_args') and len(self._args) > 0 and
+                self._args[0] == 'self')):
             self._args = self._args[1:]    # Skip 'self'.
         self._method = method
         self._instance = None    # May contain the instance this is bound to.
diff --git a/mox3/stubout.py b/mox3/stubout.py
index a02ed40..4773771 100644
--- a/mox3/stubout.py
+++ b/mox3/stubout.py
@@ -90,8 +90,8 @@ class StubOutForTesting(object):
         # Calling getattr() on a staticmethod transforms it to a 'normal'
         # function. We need to ensure that we put it back as a staticmethod.
         old_attribute = obj.__dict__.get(attr_name)
-        if (old_attribute is not None
-                and isinstance(old_attribute, staticmethod)):
+        if (old_attribute is not None and
+                isinstance(old_attribute, staticmethod)):
             orig_attr = staticmethod(orig_attr)
 
         self.stubs.append((orig_obj, attr_name, orig_attr))
diff --git a/mox3/tests/test_mox.py b/mox3/tests/test_mox.py
index 15ac565..0118ab2 100644
--- a/mox3/tests/test_mox.py
+++ b/mox3/tests/test_mox.py
@@ -110,8 +110,12 @@ class FuncTest(testtools.TestCase):
 
     def testFuncTrueFalseEvaluation(self):
         """Should return True if the validating function returns True."""
-        equals_one = lambda x: x == 1
-        always_none = lambda x: None
+
+        def equals_one(x):
+            return x == 1
+
+        def always_none(x):
+            return None
 
         self.assertTrue(mox.Func(equals_one) == 1)
         self.assertFalse(mox.Func(equals_one) == 0)
@@ -210,8 +214,8 @@ class ContainsAttributeValueTest(testtools.TestCase):
 
     def testValidPair(self):
         """Return True if the object has the key attribute that matches."""
-        self.assertTrue(mox.ContainsAttributeValue("key", 1)
-                        == self.test_object)
+        self.assertTrue(mox.ContainsAttributeValue("key", 1) ==
+                        self.test_object)
 
     def testInvalidValue(self):
         """Should return False if the value is not correct."""
@@ -1257,8 +1261,8 @@ class MockObjectTest(testtools.TestCase):
         # NOT doing dummy[index]
 
         dummy._Replay()
-        function = lambda: [x for x in dummy]
-        self.assertRaises(mox.UnexpectedMethodCallError, function)
+        self.assertRaises(mox.UnexpectedMethodCallError,
+                          lambda: [x for x in dummy])
 
     def testMockGetIter_WithSubClassOfNewStyleClass(self):
         class NewStyleTestClass(object):
diff --git a/tox.ini b/tox.ini
index 18af8a4..282cea0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,4 +26,5 @@ commands =
 
 [flake8]
 show-source = true
+ignore = E721
 exclude=.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg