code: def local_file(self, filename):
          
          LOG.info('Retrieving "%s" from "%s".', filename, self.runway_dir)
  
          file_contents = ''
  
          file_path = os.path.join(self.runway_dir, filename)
  
          try:
              with open(file_path, 'rt') as lookup_file:
                  file_contents = lookup_file.read()
          except FileNotFoundError:
              LOG.warning('File missing "%s".', file_path)
              raise
  
          LOG.debug('Local file contents:\n%s', file_contents)
          return file_contents
docs: Read the local file in _self.runway_dir_.
  
          Args:
              filename (str): Name of file to retrieve relative to root of
                  _runway_dir_.
  
          Returns:
              str: Contents of local file.
  
          Raises:
              FileNotFoundError: Requested file missing.