def lnprob(theta, x, y, yerr):
    lp = lnprior(theta)
    if (not np.isfinite(lp)):
        return (- np.inf)
    return (lp + lnlike(theta, x, y, yerr))
def lnprob(theta, x, y, yerr):
    lp = lnprior(theta)
    if (not np.isfinite(lp)):
        return (- np.inf)
    return (lp + lnlike(theta, x, y, yerr))