code: def _get_event(event_file_name):
      
  
      if event_file_name == STDIN_FILE_NAME:
          # If event is empty, listen to stdin for event data until EOF
          LOG.info("Reading invoke payload from stdin (you can also pass it from file with --event)")
  
      # click.open_file knows to open stdin when filename is '-'. This is safer than manually opening streams, and
      # accidentally closing a standard stream
      with click.open_file(event_file_name, 'r') as fp:
          return fp.read()
docs: Read the event JSON data from the given file. If no file is provided, read the event from stdin.
  
      :param string event_file_name: Path to event file, or '-' for stdin
      :return string: Contents of the event file or stdin