>>> import numpy as np
>>> # generate a 1D integer numpy array from 0 to 4
>>> def generator_1d():
...     for i in range(5):
...         yield (np.array([i]),)
>>> generator_dataset = ds.GeneratorDataset(generator_1d, column_names="col1")
>>> # [[0], [1], [2], [3], [4]]
>>> fill_op = transforms.Fill(3)
>>> generator_dataset = generator_dataset.map(operations=fill_op)
>>> # [[3], [3], [3], [3], [3]]