nargs set to '*' and help is a string 'Restricts dumped data to the specified app_label or app_label.ModelName.'. call the method parser.add_argument with 4 arguments: string '--format', default set to string 'json',
parser . add_argument ( '--format' , default = 'json' , dest = 'format' , help = 'Specifies the output serialization format for fixtures.' )