@Override
 public String generateLatex() {
   String id = "???";
   if (identifier != null) id = identifier.generateLatex();
   String thresh = "???";
   if (threshold != null) thresh = threshold.generateLatex();
   String rp = "???";
   if (rate != null) rp = rate.generateLatex();
   return " ingest(" + id + "," + thresh + " , " + rp + ")";
 }
 @Override
 public String generateLatex() {
   String op = "???";
   String left = "???";
   if (lExpr != null) left = lExpr.generateLatex();
   String right = "???";
   if (rExpr != null) right = rExpr.generateLatex();
   switch (prim) {
     case MAX:
       op = " max ";
       break;
     case MIN:
       op = " min ";
       break;
   }
   return op + "(" + left + "," + right + ")";
 }