How to use the pathspec.util.RecursionError function in pathspec

*follow_links* (:class:`bool`) is whether to walk symbolic links that
	resolve to directories.

	Yields each entry (:class:`.TreeEntry`).
	"""
	dir_full = os.path.join(root_full, dir_rel)
	dir_real = os.path.realpath(dir_full)

	# Remember each encountered ancestor directory and its canonical
	# (real) path. If a canonical path is encountered more than once,
	# recursion has occurred.
	if dir_real not in memo:
		memo[dir_real] = dir_rel
	else:
		raise RecursionError(real_path=dir_real, first_path=memo[dir_real], second_path=dir_rel)

	for node_name in os.listdir(dir_full):
		node_rel = os.path.join(dir_rel, node_name)
		node_full = os.path.join(root_full, node_rel)

		# Inspect child node.
		try:
			node_lstat = os.lstat(node_full)
		except OSError as e:
			if on_error is not None:
				on_error(e)
			continue

		if stat.S_ISLNK(node_lstat.st_mode):
			# Child node is a link, inspect the target node.
			is_link = True

def __init__(self, real_path, first_path, second_path):
		"""
		Initializes the :exc:`RecursionError` instance.

		*real_path* (:class:`str`) is the real path that recursion was
		encountered on.

		*first_path* (:class:`str`) is the first path encountered for
		*real_path*.

		*second_path* (:class:`str`) is the second path encountered for
		*real_path*.
		"""
		super(RecursionError, self).__init__(real_path, first_path, second_path)