def get_lnprior(theta, priors):
    """
    Returns the summed log-prior probability of ``theta`` given ``priors``.

    Parameters
    ----------
    theta : list
        State vector
    priors : list of Prior
        :class:`Prior` vector

    Returns
    -------
    lp : int
        Log-prior probability
    """

    assert len(theta) == len(priors)

    lp = 0.0

    # Loop over all parameters
    for i, prior in enumerate(priors):

        # Sum lnprobs
        lp += prior.lnprior(theta[i])

    return lp