def _translate_xmlbool(xmlbool):
    """ 
    Helper function which translates strings 'true' and 'false' to bool types.
    """
    if xmlbool == 'false':
        return False
    elif xmlbool == 'true':
        return True
    else:
        raise Exception('The xml boolean ' + str(xmlbool) +
            ' does not have a valid value.')
