code: def run_from_argv(self, argv):
          
          option = '--testrunner='
          for arg in argv[2:]:
              if arg.startswith(option):
                  self.test_runner = arg[len(option):]
                  break
          super(Command, self).run_from_argv(argv)
docs: Pre-parse the command line to extract the value of the --testrunner
          option. This allows a test runner to define additional command line
          arguments.