diff --git a/tensorflow/python/keras/integration_test.py b/tensorflow/python/keras/integration_test.py
index 0e6fc79dd36..dfe62276feb 100644
--- a/tensorflow/python/keras/integration_test.py
+++ b/tensorflow/python/keras/integration_test.py
@@ -318,7 +318,7 @@ class KerasIntegrationTest(test.TestCase):
     with self.cached_session():
       v = variable_scope.get_variable(
           "v",
-          shape = [4, 4],
+          shape=[4, 4],
           initializer=keras.initializers.glorot_uniform(),
           regularizer=keras.regularizers.l2(0.))
 
diff --git a/tensorflow/python/keras/regularizers.py b/tensorflow/python/keras/regularizers.py
index fd0748f3ae2..cbcdae214f9 100644
--- a/tensorflow/python/keras/regularizers.py
+++ b/tensorflow/python/keras/regularizers.py
@@ -55,12 +55,14 @@ class L1L2(Regularizer):
     self.l2 = K.cast_to_floatx(l2)
 
   def __call__(self, x):
-    regularization = ops.convert_to_tensor(0., dtype=K.floatx())
-    if self.l1:
-      regularization += math_ops.reduce_sum(self.l1 * math_ops.abs(x))
-    if self.l2:
-      regularization += math_ops.reduce_sum(self.l2 * math_ops.square(x))
-    return regularization
+    if self.l1 or self.l2:
+      regularization = ops.convert_to_tensor(0., dtype=K.floatx())
+      if self.l1:
+        regularization += math_ops.reduce_sum(self.l1 * math_ops.abs(x))
+      if self.l2:
+        regularization += math_ops.reduce_sum(self.l2 * math_ops.square(x))
+      return regularization
+    return None
 
   def get_config(self):
     return {'l1': float(self.l1), 'l2': float(self.l2)}