179     /// @notice returns the current debt rate
180     function getDebtRate() public view returns (uint256) {                                                                        
181         if (_isEthMarket) return penrose.bigBangEthDebtRate(); // default 0.5%                                                    
182         if (totalBorrow.elastic == 0) return minDebtRate;                                                                         
183         
184         uint256 _ethMarketTotalDebt = BigBang(penrose.bigBangEthMarket())                                                         
185             .getTotalDebt();                                                                                                      
186         uint256 _currentDebt = totalBorrow.elastic;
187         uint256 _maxDebtPoint = (_ethMarketTotalDebt *                                                                            
188             debtRateAgainstEthMarket) / 1e18;                                                                                     
189 
190         if (_currentDebt >= _maxDebtPoint) return maxDebtRate;
191 
192         uint256 debtPercentage = ((_currentDebt - debtStartPoint) *
193             DEBT_PRECISION) / (_maxDebtPoint - debtStartPoint);
194         uint256 debt = ((maxDebtRate - minDebtRate) * debtPercentage) /
195             DEBT_PRECISION +
196             minDebtRate;
197 
// BigBang
// borrow
247        require(amount >= debtStartPoint);
