Python3 log likelihood of Negative Binomial for binned data

log_likelihood_binned.py

def log_likelihood_binned(params, *args):
    r, p = params
    occurrences_binned = args[0]
    observed_values = np.arange(len(X_binned))
    N = np.sum(occurrences_binned)

    result = np.sum(np.multiply(occurrences_binned, gammaln(observed_values + r))) \
             - np.sum(np.multiply(occurrences_binned, np.log(factorial(observed_values)))) \
             - N * (gammaln(r)) \
             + np.sum(np.multiply(occurrences_binned, observed_values * np.log(1 - (p if p < 1 else 1 - infinitesimal)))) \
             + N * r * np.log(p)

    return -result