code: def changed_dir(dirname):
      oldcwd = os.getcwd()
      os.chdir(dirname)
      try:
          yield
      finally:
          os.chdir(oldcwd)
  
imports: import contextlib
  import os
  import os.path
  from os.path import join
  import re
  import shlex
  import sys
  import pkg_resources
  from setuptools import setup, Extension, Distribution, find_namespace_packages
  from Cython.Distutils import build_ext
  import Cython
label_desc: Use image node_id 1 for calling a global function with example usage: changed_dir(dirname) without return types