def METHOD_NAME(self, kwargs_fixed):
    """Updates fixed keyword argument list with linear parameters.
    :param kwargs_fixed: list of keyword arguments held fixed during sampling
    :return: updated keyword argument list
    """
    for k, model in enumerate(self.model_list):
        if self._fixed_magnification_list[k] is True and model in [
            "LENSED_POSITION",
            "SOURCE_POSITION",
        ]:
            kwargs_fixed[k]["source_amp"] = 1
        else:
            kwargs_fixed[k]["point_amp"] = np.ones(self._num_point_sources_list[k])
    return kwargs_fixed