code: def get_gain(poles):
      return functools.reduce(
          operator.mul, [(1.0 - z) * (1.0 - 1.0 / z) for z in poles]
      )
  
file_path: cupy/cupyx/scipy/ndimage/_spline_prefilter_core.py
imports: import functools
  import math
  import operator
  import textwrap
  import cupy
label_desc: Use image node_id 2 for calling a global function with example usage: get_gain(poles) and returns: functools