add Union import

"""This module contains a linting function for a tool's help."""

from typing import Union

from galaxy.util import (

    rst_to_html,

    unicodify,

        lint_ctx.valid("Help contains valid reStructuredText.", node=helps[0])

def rst_invalid(text):

def rst_invalid(text: str) -> Union[bool, str]:

    """

    Predicate to determine if text is invalid reStructuredText.

    Return False if the supplied text is valid reStructuredText or