code: def __call__(
      self,
  ) -> Union[Tuple[List[str], List[str]], Tuple[str, str]]:
      """The return value of the gatherer is a tuple of two lists or strings.
  
      The first element is the list of image paths or the directory of the
      images. The second element is the list of annotation paths or the path
      of the annotation file which contains all the annotations.
      """
      raise NotImplementedError
  
imports: import os.path
  from typing import List, Optional, Tuple, Union
label_desc: Use image node_id 2 for calling the BaseGatherer obj's underlying member method code with example usage: obj.__call__() without return types