diff --git a/django/db/backends/oracle/operations.py b/django/db/backends/oracle/operations.py
index ed42fcb3cf..1cd17a2af1 100644
--- a/django/db/backends/oracle/operations.py
+++ b/django/db/backends/oracle/operations.py
@@ -245,7 +245,7 @@ WHEN (new.%(col_name)s IS NULL)
         # http://cx-oracle.sourceforge.net/html/cursor.html#Cursor.statement
         # The DB API definition does not define this attribute.
         statement = cursor.statement
-        if statement and six.PY2 and not isinstance(statement, unicode):
+        if statement and six.PY2 and not isinstance(statement, unicode):  # NOQA: unicode undefined on PY3
             statement = statement.decode('utf-8')
         # Unlike Psycopg's `query` and MySQLdb`'s `_last_executed`, CxOracle's
         # `statement` doesn't contain the query parameters. refs #20010.
diff --git a/django/db/utils.py b/django/db/utils.py
index 534a4d5c20..8a27fdc0e2 100644
--- a/django/db/utils.py
+++ b/django/db/utils.py
@@ -17,7 +17,7 @@ DEFAULT_DB_ALIAS = 'default'
 DJANGO_VERSION_PICKLE_KEY = '_django_version'
 
 
-class Error(Exception if six.PY3 else StandardError):
+class Error(Exception if six.PY3 else StandardError):  # NOQA: StandardError undefined on PY3
     pass
 
 
diff --git a/django/utils/functional.py b/django/utils/functional.py
index f3a36b318d..84f4227784 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -285,7 +285,7 @@ class LazyObject(object):
         __bool__ = new_method_proxy(bool)
     else:
         __str__ = new_method_proxy(str)
-        __unicode__ = new_method_proxy(unicode)
+        __unicode__ = new_method_proxy(unicode)  # NOQA: unicode undefined on PY3
         __nonzero__ = new_method_proxy(bool)
 
     # Introspection support
diff --git a/django/utils/html.py b/django/utils/html.py
index cafc3ab6e1..bbdc03f3c6 100644
--- a/django/utils/html.py
+++ b/django/utils/html.py
@@ -380,7 +380,7 @@ def html_safe(klass):
             )
         klass_unicode = klass.__unicode__
         klass.__unicode__ = lambda self: mark_safe(klass_unicode(self))
-        klass.__html__ = lambda self: unicode(self)
+        klass.__html__ = lambda self: unicode(self)  # NOQA: unicode undefined on PY3
     else:
         if '__str__' not in klass.__dict__:
             raise ValueError(
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index 24951633de..a4e6fc9fc2 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -208,7 +208,10 @@ class TranslationTests(SimpleTestCase):
         result = ungettext_lazy('%(name)s has %(num)d good result', '%(name)s has %(num)d good results', 4)
         self.assertEqual(result % {'name': 'Joe', 'num': 4}, "Joe has 4 good results")
         # Now with a long
-        result = ungettext_lazy('%(name)s has %(num)d good result', '%(name)s has %(num)d good results', long(4))
+        result = ungettext_lazy(
+            '%(name)s has %(num)d good result', '%(name)s has %(num)d good results',
+            long(4)   # NOQA: long undefined on PY3
+        )
         self.assertEqual(result % {'name': 'Joe', 'num': 4}, "Joe has 4 good results")
 
     @override_settings(LOCALE_PATHS=extended_locale_paths)
@@ -470,7 +473,7 @@ class FormattingTests(SimpleTestCase):
         self.d = datetime.date(2009, 12, 31)
         self.dt = datetime.datetime(2009, 12, 31, 20, 50)
         self.t = datetime.time(10, 15, 48)
-        self.l = 10000 if PY3 else long(10000)
+        self.l = 10000 if PY3 else long(10000)  # NOQA: long undefined on PY3
         self.ctxt = Context({
             'n': self.n,
             't': self.t,
diff --git a/tests/model_fields/tests.py b/tests/model_fields/tests.py
index 939ba269d8..353c15f491 100644
--- a/tests/model_fields/tests.py
+++ b/tests/model_fields/tests.py
@@ -797,10 +797,11 @@ class PromiseTest(test.SimpleTestCase):
 
     @unittest.skipIf(six.PY3, "Python 3 has no `long` type.")
     def test_BigIntegerField(self):
-        lazy_func = lazy(lambda: long(9999999999999999999), long)
+        # NOQA: long undefined on PY3
+        lazy_func = lazy(lambda: long(9999999999999999999), long)  # NOQA
         self.assertIsInstance(
             BigIntegerField().get_prep_value(lazy_func()),
-            long)
+            long)  # NOQA
 
     def test_BinaryField(self):
         lazy_func = lazy(lambda: b'', bytes)
diff --git a/tests/queries/tests.py b/tests/queries/tests.py
index 71c32c6bda..36bbdfea29 100644
--- a/tests/queries/tests.py
+++ b/tests/queries/tests.py
@@ -2245,17 +2245,18 @@ class QuerySetSupportsPythonIdioms(TestCase):
 
     @unittest.skipUnless(six.PY2, "Python 2 only -- Python 3 doesn't have longs.")
     def test_slicing_works_with_longs(self):
-        self.assertEqual(self.get_ordered_articles()[long(0)].name, 'Article 1')
-        self.assertQuerysetEqual(self.get_ordered_articles()[long(1):long(3)],
+        # NOQA: long undefined on PY3
+        self.assertEqual(self.get_ordered_articles()[long(0)].name, 'Article 1')  # NOQA
+        self.assertQuerysetEqual(self.get_ordered_articles()[long(1):long(3)],  # NOQA
             ["<Article: Article 2>", "<Article: Article 3>"])
-        self.assertQuerysetEqual(self.get_ordered_articles()[::long(2)],
+        self.assertQuerysetEqual(self.get_ordered_articles()[::long(2)],  # NOQA
             ["<Article: Article 1>",
             "<Article: Article 3>",
             "<Article: Article 5>",
             "<Article: Article 7>"])
 
         # And can be mixed with ints.
-        self.assertQuerysetEqual(self.get_ordered_articles()[1:long(3)],
+        self.assertQuerysetEqual(self.get_ordered_articles()[1:long(3)],  # NOQA
             ["<Article: Article 2>", "<Article: Article 3>"])
 
     def test_slicing_without_step_is_lazy(self):