code: def __call__(self, y: np.ndarray) -> float:
      y = self._input_converter(y)
      return (y * self._w).sum() / self._w.sum()
  
imports: from __future__ import annotations
  import abc
  from typing import Callable
  from typing import Union
  import numpy
label_desc: Use image node_id 2 for calling the WeightedSumReductionTransformation obj's underlying member method code with example usage: obj.__call__(y) and returns: unknown