code: public ReduceInit by(ValueElement valueExpression) {
  		CollectExpression collXpr = (CollectExpression)this.astNode;
  		ReduceEvalExpression reduceEval = (ReduceEvalExpression)(collXpr).getEvalExpression();
  		reduceEval.setReduceExpression(valueExpression);
  		ReduceInit ret = new ReduceInit(collXpr);
  		return ret;
  	}
docs: <div color='red' style="font-size:24px;color:red"><b><i><u>JCYPHER</u></i></b></div>
  <div color='red' style="font-size:18px;color:red"><i>specify an expression to be evaluated against individual elements of a collection in the context of a REDUCE expression.
  </br>The result of each evaluation is accumulated in a variable</i></div>
  <div color='red' style="font-size:18px;color:red"><i>e.g. ...REDUCE()<br/>.fromAll(n).IN_nodes(p)<br/>.to(totalAge)<br/>.<b>by(totalAge.plus(n.numberProperty("age")))</b><br/>.startWith(0)</i></div>
  <br/>