'Return key-value dict with metadata from @decorators.idempotent_id'

@staticmethod
def _get_idempotent_id(test_node):

    idempotent_id = None
    for decorator in test_node.decorator_list:
        if (hasattr(decorator, 'func') and hasattr(decorator.func, 'attr') and (decorator.func.attr == DECORATOR_NAME) and hasattr(decorator.func, 'value') and (decorator.func.value.id == DECORATOR_MODULE)):
            for arg in decorator.args:
                idempotent_id = ast.literal_eval(arg)
    return idempotent_id
