code: def update(self, command=None, **kwargs):
          
          if command is None:
              argparser = self.argparser
          else:
              argparser = self[command]
  
          for k,v in kwargs.items():
              setattr(argparser, k, v)
docs: update data, which is usually passed in ArgumentParser initialization
  
          e.g. command.update(prog="foo")