 function mergeTranches(uint256 _loanId, Loan memory _loan, uint256 _minTranche, uint256 _maxTranche)
        external
        returns (uint256, Loan memory)
    {
        _baseLoanChecks(_loanId, _loan);
        uint256 loanId = _getAndSetNewLoanId();
        Loan memory loanMergedTranches = _mergeTranches(loanId, _loan, _minTranche, _maxTranche);
        _loans[loanId] = loanMergedTranches.hash();
        delete _loans[_loanId];

        emit TranchesMerged(loanMergedTranches, _minTranche, _maxTranche);

        return (loanId, loanMergedTranches);
    }
 function mergeTranches(uint256 _loanId, Loan memory _loan, uint256 _minTranche, uint256 _maxTranche)
        external
+       nonReentrant
        returns (uint256, Loan memory)
    {
        _baseLoanChecks(_loanId, _loan);
        uint256 loanId = _getAndSetNewLoanId();

    function refinancePartial(RenegotiationOffer calldata _renegotiationOffer, Loan memory _loan)
        external
+       nonReentrant
        returns (uint256, Loan memory)
    {
