def __add__(self, datasets):
        """
        Concat the datasets in the input list of datasets. 

        Note:
        The column name，column data type and rank of column data should be the same in input datasets.

        Args:
            datasets (list or class Dataset): A list of datasets or a single class Dataset
                to be concated together with this dataset.

        Returns:
            ConcatDataset, dataset concated.

        Examples:
            >>> import mindspore.dataset as ds
            >>> # ds1 and ds2 are instances of Dataset object
            >>> # creates a dataset by concating ds1 and ds2
            >>> data1 = ds1 + ds2
        """

import mindspore.dataset as ds

def generator_3():
      for i in range(3):
            yield (np.array([i]), )

def generator_10():
      for i in range(3, 10):
            yield (np.array([i]), )


def test_concat_01():
    """
    Test concat: test concat 2 datasets that have the same column name and data type
    """
    data1 = ds.GeneratorDataset(generator_3, ["col1"])
    data2 = ds.GeneratorDataset(generator_10, ["col1"])
    
    data3 = data1 + data2

    # Here i refers to index, d refers to data element 
    for i, d in enumerate(data3):
        logger.info("data:", d[0][0])
        assert i == d[0][0]

    assert sum([1 for _ in data3]) == 10

0, 1, 2, 3, 4,5,6,7,8,9