code: def formats(input_formats, output_formats, debug=False):
      
      if input_formats == output_formats:
          show_inputs, show_outputs = True, True
      else:
          show_inputs, show_outputs = input_formats, output_formats
  
      if show_inputs:
          click.echo("input formats:")
          for driver in available_input_formats():
              click.echo("- %s" % driver)
      if show_outputs:
          click.echo("output formats:")
          for driver in available_output_formats():
              click.echo("- %s" % driver)
docs: List input and/or output formats.