docstr: get fetch list of model
docstr_tok: ["get","fetch","list","of","model"]
code: def fetches(self):
      "get fetch list of model"
      raise NotImplementError(self, self.fetches)
  
imports: import os
  import logging
  import paddle.fluid
label_desc: Use image node_id 8 for calling the ModelBase obj's underlying member method code with example usage: obj.fetches() without return types