def REVERSE_ARRAY(expression):
    """
    Accepts an array expression as an argument and returns an array with the elements in reverse order.
    See https://docs.mongodb.com/manual/reference/operator/aggregation/reverseArray/
    for more details
    :param expression: Any valid expression as long as it resolves to an array.
    :return: Aggregation operator
    """
    return {'$reverseArray': expression}
