def METHOD_NAME(cps_pixel, exposure_time):
    """Computes the variance of the shot noise Gaussian approximation of Poisson noise
    term.
    :param cps_pixel: counts per second of the intensity per pixel unit
    :param exposure_time: total exposure time (in units seconds or equivalent unit as
        cps_pixel)
    :return: sqrt(variance) of pixel value
    """
    return cps_pixel / np.sqrt(exposure_time)