File description update. Setting default number of species to 1, instead of None.
File description update. Setting default number of species to 1, instead of None.

PiperOrigin-RevId: 394931787

google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research,google-research/google-research