docs: def NormalizePath(path, sep="/"):
    """A sane implementation of os.path.normpath.
  
    The standard implementation treats leading / and // as different leading to
    incorrect normal forms.
  
    NOTE: Its ok to use a relative path here (without leading /) but any /../ will
    still be removed anchoring the path at the top level (e.g. foo/../../../../bar
    => bar).
  
    Args:
       path: The path to normalize.
       sep: Separator used.
  
    Returns:
       A normalized path. In this context normalized means that all input paths
       that would result in the system opening the same physical file will produce
       the same normalized path.
    """
    if not path:
      return sep
    path = SmartUnicode(path)
  
    path_list = path.split(sep)
  
    # This is a relative path and the first element is . or ..
    if path_list[0] in [".", "..", ""]:
      path_list.pop(0)
  
    # Deliberately begin at index 1 to preserve a single leading /
    i = 0
  
    while True:
      list_len = len(path_list)
  
      # We begin at the last known good position so we never iterate over path
      # elements which are already examined
      for i in range(i, len(path_list)):
        # Remove /./ form
        if path_list[i] == "." or not path_list[i]:
          path_list.pop(i)
          break
  
        # Remove /../ form
        elif path_list[i] == "..":
          path_list.pop(i)
          # Anchor at the top level
          if (i == 1 and path_list[0]) or i > 1:
            i -= 1
            path_list.pop(i)
          break
  
      # If we didnt alter the path so far we can quit
      if len(path_list) == list_len:
        return sep + sep.join(path_list)