dest as a string 'all' default as boolean False and help as a string 'Updates the message files for all existing locales.'. call the method parser.add_argument with 5 arguments: string '--extension', string '-e', dest set to string 'extensions',
parser . add_argument ( '--extension' , '-e' , dest = 'extensions' , help = 'The file extension(s) to examine (default: "html,txt", or "js" ' 'if the domain is "djangojs"). Separate multiple extensions with ' 'commas, or use -e multiple times.' , action = 'append' )