How does pymc3 handle n=0 in Binomial discrete likelihood function

Questions
6

The logp seems to have the constraint that n must be nonzero:

import pymc as pm
pm.logp(pm.Binomial.dist(n=0, p=0.5), 0).eval()

Raises

aeppl.logprob.ParameterValueError: n > 0, 0 <= p <= 1