code: def _normalization(norm, forward):
      """Returns the pypocketfft normalization mode from the norm argument"""
      try:
          inorm = _NORM_MAP[norm]
          return inorm if forward else (2 - inorm)
      except KeyError:
          raise ValueError(
              f"Invalid norm value {norm!r}, should "
              'be "backward", "ortho" or "forward"'
          ) from None
  
file_path: scipy/scipy/fft/_pocketfft/helper.py
imports: from numbers import Number
  import operator
  import os
  import threading
  import contextlib
  import numpy
  from .pypocketfft import good_size
label_desc: Use image node_id 7 for calling a global function with example usage: _normalization(norm, forward) and returns: unknown