Tiny set for testing.

def rlmb_ppo_tiny():
  """Tiny set for testing."""
  hparams = rlmb_ppo_base()
  hparams = hparams.override_from_dict(_rlmb_tiny_overrides())
  update_hparams(hparams, dict(
      ppo_epochs_num=2,
      ppo_epoch_length=10,
      real_ppo_epoch_length=36,
      real_ppo_effective_num_agents=2,
      real_batch_size=1,
      eval_batch_size=1,
  ))
  return hparams