MaxComput中 models包没有listfunctionsrequest这个类，什么原因？

class ListFunctionsRequest(object):
"""ListFunctionsRequest message."""

def init(self, project_id, location, page_size=None, page_token=None):
"""Constructor.

   Args:
       project_id (str): The project ID.
       location (str): The location of the function.
       page_size (int): The maximum number of functions to return.
       page_token (str): The next_page_token value returned from a previous List request, if any.
   """
   self.project_id = project_id
   self.location = location
   self.page_size = page_size
   self.page_token = page_token