import pymc as pm

obs = np.array([0, 0, 1])

uni = pm.Uniform("prop", 0, 1)
fake_obs = pm.Bernoulli("fake_obs", uni, size=3)


@pm.deterministic
def accept(uni=uni, fake_obs=fake_obs, obs=obs):
    if np.array_equal(fake_obs, obs):
        return uni
    else:
        return None

mcmc = pm.MCMC([uni, fake_obs, accept])

mcmc.sample(10000)

samples = mcmc.trace('accept')[:]

hist(samples[samples > 0])

samples[:1000]