function addProposalDoc(bytes32 _proposalId, bytes32 _newDoc)
        public
    {
        senderCanDoProposerOperations();
        require(isFromProposer(_proposalId));
        bytes32 _finalVersion;
        (,,,,,,,_finalVersion,,) = daoStorage().readProposal(_proposalId);
        require(_finalVersion != EMPTY_BYTES);
        daoStorage().addProposalDoc(_proposalId, _newDoc);

        emit AddProposalDoc(_proposalId, _newDoc);
    }