old_contents: #
  # Copyright 2018 Analytics Zoo Authors.
  #
  # 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.
  #
  
  from .model import KerasModel
  from .estimator import TFEstimator
  from .tf_optimizer import TFOptimizer
  from .tf_dataset import TFDataset
  from .zoo_optimizer import ZooOptimizer
  from .tf_predictor import TFPredictor
  from .tfnet import TFNet
  
new_contents: #
  # Copyright 2018 Analytics Zoo Authors.
  #
  # 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.
  #
  
  
  def check_tf_version():
      import logging
      try:
          import tensorflow as tf
      except Exception as e:
          raise RuntimeError("Importing TensorFlow failed, please install tensorflow 1.15.0.", e)
  
      v_str = tf.__version__
      major, minor, patch = v_str.split(".")
      if v_str != "1.15.0":
          if int(major) == 1:
              logging.warning("\n######################### WARNING ##########################\n"
                              "\nAnalytics Zoo TFPark has only been tested on TensorFlow 1.15.0,"
                              " but your current TensorFlow installation is {}.".format(v_str) +
                              "\nYou may encounter some version incompatibility issues. "
                              "\n##############################################################")
          else:
              message = "Currently Analytics Zoo TFPark only supports TensorFlow 1.15.0, " + \
                        "but your current TensorFlow installation is {}".format(v_str)
              raise RuntimeError(message)
  
  check_tf_version()
  
  from .model import KerasModel
  from .estimator import TFEstimator
  from .tf_optimizer import TFOptimizer
  from .tf_dataset import TFDataset
  from .zoo_optimizer import ZooOptimizer
  from .tf_predictor import TFPredictor
  from .tfnet import TFNet
  
subject: Add tensorflow version check (#2459)