def _estimate_mean(mweights, proppts):
    """See BFaS; p. 88.

    Parameters
    ----------
    mweights: np.ndarray, shape (2*dimension + 1,)
        Constant mean weights for unscented transform.
    proppts: np.ndarray, shape (2*dimension + 1, dimension)
        Propagated sigma points

    Returns
    -------
    np.ndarray, shape (dimension,)
        Estimated mean.
    """
    return mweights @ proppts