'Loads definition_xml stored in a dedicated file'

@classmethod
def load_definition_xml(cls, node, runtime, def_id):

    url_name = cls._get_url_name(node)
    filepath = cls._format_filepath(node.tag, name_to_pathname(url_name))
    definition_xml = cls.load_file(filepath, runtime.resources_fs, def_id)
    return (definition_xml, filepath)
