Getting acceptance of numpy metropolis_hastings

Created by: VolodyaCO

The method defining the acceptance for numpy/metropolis_hastings in v3.0 is

@property
def acceptance(self):
    """The measured acceptance probability."""
    return _mean(self._accepted_samples) / _mean(self._total_samples)

But self._accepted_samples and self._total_samples are ints. Don't know if this has been fixed in a PR, but if it's not, maybe it should be included.