anchor.diff:    }
     
     get minPayment => _minPayment;
  -  set minPayment(double value) {
  +  set minPayment(num value) {
       if (value.isNegative) {
         throw new Exception('Minimum payment cannot be negative');
       }
  
positive.code:   }
    
    get balance => _balance;
    set balance(double value) {
      if (value.isNegative) {
        throw new Exception('Balance cannot be negative');
      }
  
negative.code:   }
    
    get rate => _rate;
    set rate(num value) {
      if (value.isNegative) {
        throw new Exception('Rate cannot be negative');
      }
  