old_contents: # Copyright 2015 Amazon.com, Inc. or its affiliates. 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. A copy of
  # the License is located at
  #
  # http://aws.amazon.com/apache2.0/
  #
  # or in the "license" file accompanying this file. This file 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.
  import sys
  import os
  
  
  if sys.platform.startswith('win'):
      def rename_file(current_filename, new_filename):
          try:
              os.remove(new_filename)
          except OSError:
              pass
          os.rename(current_filename, new_filename)
  else:
      rename_file = os.rename
  
new_contents: # Copyright 2015 Amazon.com, Inc. or its affiliates. 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. A copy of
  # the License is located at
  #
  # http://aws.amazon.com/apache2.0/
  #
  # or in the "license" file accompanying this file. This file 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.
  import sys
  import os
  import errno
  
  
  if sys.platform.startswith('win'):
      def rename_file(current_filename, new_filename):
          try:
              os.remove(new_filename)
          except OSError as e:
              if not e.errno == errno.ENOENT:
                  # We only want to a ignore trying to remove
                  # a file that does not exist.  If it fails
                  # for any other reason we should be propagating
                  # that exception.
                  raise
          os.rename(current_filename, new_filename)
  else:
      rename_file = os.rename
  
subject: Handle the case where OSError is not because file does not exist