def _limb_darkened_profile(limb_dark_law, LDCs, mu):
    """Returns limb-darkened flux

    Args:
        limb_dark_law (str): 'quadratic'
        LDCs (numpy array): limb-darkening coefficients
            Must have two elements for 'quadratic'
        mu (numpy array): cos of the angle between the line-of-sight and the
            normal to a grid element of the host's surface

    Returns:
        numpy array: normalized flux profile

    """

    if((limb_dark_law == 'quadratic') and (len(LDCs) == 2)):
        return 1. - LDCs[0]*(1. - mu) - LDCs[1]*(1. - mu)*(1. - mu)
    else:
        raise ValueError("Only quadratic limb-darkening law allowed, "+
                "which requires two coefficients!")