code: def set_backend(backend):
      """Set the parallel backend to use during estimation.
  
      Parameters
      ----------
      backend : str
          backend type, one of 'multiprocessing', 'threading', 'sequential'
      """
      global _BACKEND
      _BACKEND = backend
  
imports: from __future__ import print_function
  import os
  import sys
  import shutil
  import tempfile
  import warnings
  import sysconfig
  import subprocess
  from multiprocessing import current_process
  import numpy
label_desc: Use image node_id 10 for calling a global function with example usage: set_backend(backend) without return types