    def next_epoch_idx(self):
        """Return the epoch index after *next_epoch_itr* is called."""

        epochs = [itr.next_epoch_idx for itr in self.iterators]
        self.epoch = epochs[0]
        assert all(epoch == self.epoch for epoch in epochs)

        return self.epoch
Return the epoch index after *next_epoch_itr* is called.
examples/laser/laser_src/multitask_data_utils.py