nl: usage set to return value of the method self.usage called with an argument subcommand, version set to return value of the method self.get_version. call the method parser.add_option with 8 arguments: string '-v', string '--verbosity', action set to string 'store',
code: parser . add_option ( '-v' , '--verbosity' , action = 'store' , dest = 'verbosity' , default = '1' , type = 'choice' , choices = [ '0' , '1' , '2' , '3' ] , help = 'Verbosity level; 0=minimal output, 1=normal output, 2=verbose output, 3=very verbose output' )