@staticmethod
    @ngjit
    def _append(x, y, m2, field, sum, count):
        # sum & count are the results of sum[y, x], count[y, x] before being
        # updated by field
        if not np.isnan(field):
            if count == 0:
                m2[y, x] = 0
            else:
                u1 = count / np.float64(sum)
                u = np.float64(sum + field) / (count + 1)
                m2[y, x] += (field - u1) * (field - u)
dataset/ETHPy150Open bokeh/datashader/datashader/reductions.py/m2._append/swapped operands of `/`