From 4a51ba228b2c416a115aee3bc034683eb02482c3 Mon Sep 17 00:00:00 2001
From: Illia Volochii <illia.volochii@gmail.com>
Date: Tue, 27 Dec 2016 16:42:17 +0200
Subject: [PATCH] Fixed #27642 -- Made forms.utils.flatatt() omit 'None' values
 from attrs.

---
 django/forms/utils.py                 | 2 +-
 tests/forms_tests/tests/test_utils.py | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/django/forms/utils.py b/django/forms/utils.py
index dc4df86058..88086b2c64 100644
--- a/django/forms/utils.py
+++ b/django/forms/utils.py
@@ -40,7 +40,7 @@ def flatatt(attrs):
         if isinstance(value, bool):
             if value:
                 boolean_attrs.append((attr,))
-        else:
+        elif value is not None:
             key_value_attrs.append((attr, value))
 
     return (
diff --git a/tests/forms_tests/tests/test_utils.py b/tests/forms_tests/tests/test_utils.py
index a6a2d81b9f..f95c956322 100644
--- a/tests/forms_tests/tests/test_utils.py
+++ b/tests/forms_tests/tests/test_utils.py
@@ -34,6 +34,7 @@ class FormsUtilsTestCase(SimpleTestCase):
             flatatt({'class': "news", 'title': "Read this", 'required': False}),
             ' class="news" title="Read this"'
         )
+        self.assertEqual(flatatt({'class': None}), '')
         self.assertEqual(flatatt({}), '')
 
     def test_flatatt_no_side_effects(self):