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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def patched_packing_env(env):
 """Monkey patch packaging.markers.default_environment"""

  old_env = pkg_resources.packaging.markers.default_environment
  new_env = lambda: env
  pkg_resources._vendor.packaging.markers.default_environment = new_env
  try:
    yield
  finally:
    pkg_resources._vendor.packaging.markers.default_environment = old_env