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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 _ListDir(dirpath, pathtype):
 """Returns children of a given directory. This function is intended to be used by the `PathComponent` subclasses to get initial list of potential children that then need to be filtered according to the rules of a specific component. Args: dirpath: A path to the directory. pathtype: The pathtype to use. Raises: ValueError: in case of unsupported path types. """

  pathspec = rdf_paths.PathSpec(path=dirpath, pathtype=pathtype)
  childpaths = []
  try:
    file_obj = vfs.VFSOpen(pathspec)
    for path in file_obj.ListNames():
      # For Windows registry, ignore the empty string which corresponds to the
      # default value in the current key. Otherwise, globbing a key will yield
      # the key itself, because joining the name of the default value u"" with
      # a key name yields the key name again.
      if pathtype != rdf_paths.PathSpec.PathType.REGISTRY or path:
        childpaths.append(path)
  except IOError:
    pass

  return childpaths