接受包含数字的PCollection，按照模4取余的结果对数字分组，计算每组最大的3个数字并将 结果通过(group, number)形式返回 Args: numbers (PCollection): 输入PCollection，必须全部为数字 Returns: PCollection: 输出 >>> input_data = _pipeline.parallelize([1, 2, 3, 9, 8, 7, 4, 5, 6, 10, 11, 12, 15, 14, 13]) >>> print input_da
(numbers)
source not stored for this graph (policy: none)
nothing calls this directly
no test coverage detected