Raise an error if a task has no splits. In estimating the approximate mixing proportions, be forgiving of missing keys in the sequence_length map.  This code makes a lot of assumptions, like that there is no preprocessing, and there is no guarantee that keys in the TFDS will also be present in the output features.
Raise an error if a task has no splits.
In estimating the approximate mixing proportions, be forgiving of missing keys in the sequence_length map.  This code makes a lot of assumptions, like that there is no preprocessing, and there is no guarantee that keys in the TFDS will also be present in the output features.

PiperOrigin-RevId: 360698862

google/seqio