old_contents: from __future__ import print_function
  
  import keras
  import sys
  
  minimum_keras_version = 2, 1, 3
  
  
  def keras_version():
      return tuple(map(int, keras.__version__.split('.')))
  
  
  def keras_version_ok():
      return keras_version() >= minimum_keras_version
  
  
  def assert_keras_version():
      detected = keras.__version__
      required = '.'.join(map(str, minimum_keras_version))
      assert(keras_version() >= minimum_keras_version), 'You are using keras version {}. The minimum required version is {}.'.format(detected, required)
  
  
  def check_keras_version():
      try:
          assert_keras_version()
      except AssertionError as e:
          print(e, file=sys.stderr)
          sys.exit(1)
  
new_contents: """
  Copyright 2017-2018 Fizyr (https://fizyr.com)
  
  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 __future__ import print_function
  
  import keras
  import sys
  
  minimum_keras_version = 2, 1, 3
  
  
  def keras_version():
      return tuple(map(int, keras.__version__.split('.')))
  
  
  def keras_version_ok():
      return keras_version() >= minimum_keras_version
  
  
  def assert_keras_version():
      detected = keras.__version__
      required = '.'.join(map(str, minimum_keras_version))
      assert(keras_version() >= minimum_keras_version), 'You are using keras version {}. The minimum required version is {}.'.format(detected, required)
  
  
  def check_keras_version():
      try:
          assert_keras_version()
      except AssertionError as e:
          print(e, file=sys.stderr)
          sys.exit(1)
  
subject: Add missing license information.