anchor.diff:      return out;
     }
   
  -  /// Divide two curves element by element. ONLY divide buckets that exist
  -  /// in both curves.  This is different behavior than addition/subtraction.
  +  /// Divide two curves element by element.
  +  /// If the curves don't match buckets, nothing is done (strict).
     PriceCurve operator /(PriceCurve other) {
       var zs = align(other);
       var out = PriceCurve();
  
positive.code:   }
  
    /// Subtract two curves element by element.
    /// Most commonly the [other] curve will have the same buckets as this
    /// curve for a given term.  If they don't, the missing bucket is replaced
    /// with zero in the subtraction.
    PriceCurve operator -(PriceCurve other) {
      var zs = align(other);
      var out = PriceCurve();
  
negative.code:   }
  
    /// Add two curves observation by observation and bucket by bucket.
    /// If the curves don't match buckets, nothing is done (strict).
    ///
    @override
    PriceCurve operator +(PriceCurve other) {
      var zs = align(other);
  