docstr: build input Variable
docstr_tok: ["build","input","Variable"]
code: def build_input(self, use_dataloader):
      "build input Variable"
      raise NotImplementError(self, self.build_input)
  
imports: import os
  import logging
  import paddle.fluid
label_desc: Use image node_id 3 for calling the ModelBase obj's underlying member method code with example usage: obj.build_input(use_dataloader) without return types