code: def __call__(self, a: typing.Any, b: typing.Any, **kwargs) -> float:
      ...
  
file_path: river/river/neighbors/base.py
imports: from __future__ import annotations
  import abc
  import typing
  from river import base
label_desc: Use image node_id 1 for calling the DistanceFunc obj's underlying member method code with example usage: obj.__call__(a, b) without return types