def XML_fromstring(content, source=None):
    """Parses the XML string into a node tree. If an ParseError exception is raised,
    the error message is formatted nicely to show the badly formed XML to the user.
    """
    try:
        tree = ET.fromstring(content)
    except ET.ParseError as err:
        x_parse_error(err, content, source)
    return tree