code: def __call__(self, x: np.ndarray) -> np.ndarray:
      if not x.size == self.indim:
          raise ValueError(
              f"Got size {x.size} but expected {self.indim}"
          )
      return x[self.indices]
  
imports: from typing import List, Callable, Optional
  from math import exp, sqrt
  import numpy
label_desc: Use image node_id 2 for calling the Indexing obj's underlying member method code with example usage: obj.__call__(x) and returns: x