nl: dest is 'use_base_manager', default is boolean False and help is a string '(use multiple --exclude to exclude multiple apps/models).'. call the method parser.add_argument with 3 arguments: string '--pks', dest set to string 'primary_keys',
code: parser . add_argument ( '--pks' , dest = 'primary_keys' , help = "Only dump objects with given primary keys. " "Accepts a comma separated list of keys. " "This option will only work when you specify one model." )