Add __init__.py in keras/distribute directory.

PiperOrigin-RevId: 242800284

tensorflow/python/keras/distribute/BUILD

@@ -13,6 +13,7 @@ exports_files(["LICENSE"])
 py_library(
     name = "distribute",
     srcs = [
+        "__init__.py",
         "distributed_training_utils.py",
     ],
     srcs_version = "PY2AND3",
@@ -329,6 +330,7 @@ cuda_py_test(
     name = "multi_worker_callback_test",
     srcs = ["multi_worker_callback_test.py"],
     additional_deps = [
+        ":distribute",
         ":multi_worker_test_main_lib",
         "//tensorflow/python:platform",
         "//tensorflow/python/distribute:collective_all_reduce_strategy",

tensorflow/python/keras/distribute/__init__.py

@@ -0,0 +1,19 @@
+# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Keras' Distribution Strategy library."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function