code: def _norm_path(path):
      if path is None:
          return None
      assert isinstance(path, six.string_types)
      if "\\" in path:
          raise AssertionError(
              "path {} contains Windows seprators \\ - replace them with '/'".format(
                  path
              )
          )
      return os.path.normpath(path)
  
imports: import errno
  import functools
  import json
  import os
  import sys
  import threading
  import six
label_desc: Use image node_id 4 for calling a global function with example usage: _norm_path(path) and returns: os, None