fix docstring (#19221)

diff --git a/tensorflow/python/ops/variable_scope.py b/tensorflow/python/ops/variable_scope.py
index e33085b..8b9742f 100644
--- a/tensorflow/python/ops/variable_scope.py
+++ b/tensorflow/python/ops/variable_scope.py
@@ -1227,7 +1227,7 @@
     for input in dataset_iterator:
       with container.as_default():
         x = tf.layers.dense(input, name="l1")
-    print(container.variables)  # Should print the variables used in the layer.
+    print(container.variables())  # Should print the variables used in the layer.
   ```
   """