FunctionDataSource does not allow function with 3 positional arguments thus shuffling does not work about seqio HOT 2 OPEN

Hi @marton-avrios , this is working as intended iiuc. The first validation checks that the dataset_fn should have at least the split and shuffle_files as args, since seed may not be an arg. The second validation is triggered only when the user passes a seed when loading the dataset, meaning that the dataset_fn is expected to have a "seed" arg. "seeds" isn't supported. If your dataset_fn needs multiple seeds, then you can create new ones from the initial seed,

from seqio.

Maybe the fn needs a better name and documentation, but it doesn't validate that the fn has exactly the same args as expected_pos_args, but that the first len(expected_pos_args) are exactly the same

from seqio.