code: def pull_image(self, name, tag='latest'):
          
          name = "{0}/{1}:{2}".format(DOCKER_NEG, name, tag)
          return "/dockerapi/v2/images", dict(image=name)
docs: pull the image from repository
  
          :param name: `class`:`str`, without docker.neg prefix, invalid like: 'centos'
          :param tag: `class`:`str`, special the image's version
          :return: (`class`:`int`, `class`:`object`)