code: def execute(self):
          
          # Preprocess options to extract --settings and --pythonpath.
          # These options could affect the commands that are available, so they
          # must be processed early.
          parser = NewOptionParser(prog=self.prog_name,
                               usage=self.usage_info,
  #                             version=self.get_version(),
                               formatter = NewFormatter(),
                               add_help_option = False,
                               option_list=self.option_list)
  
          options, args = parser.parse_args(self.argv)
          self.options = options
          if len(args) == 0:
              self.message("You should give at least one package name.", 'error')
              return
  
          subcommand = args[0]
  
          self.handle(args[1:], self.options, self.global_options, subcommand)
docs: Given the command-line arguments, this figures out which subcommand is
          being run, creates a parser appropriate to that command, and runs it.