def METHOD_NAME(vouch_matrix: NDArray) -> NDArray:
    """
    Returns the weighted_vouch_matrix, derived from the vouch_matrix
    (composed of explicit Voucher created by users).
    The weighted_vouch_matrix integrates implicit vouches, i.e vouches
    attributed to a sink, such as the sum of weighted vouches given by
    any voucher is at most one.
    """
    n_vouches_by_voucher = vouch_matrix.sum(axis=1)
    weighted_denominator = n_vouches_by_voucher + SINK_VOUCH
    weighted_vouch_matrix = vouch_matrix / weighted_denominator[:, np.newaxis]
    return weighted_vouch_matrix