code: public RDistinct DISTINCT() {
  		ReturnExpression rx = getReturnExpression();
  		rx.setDistinct();
  		RDistinct ret = new RDistinct(rx);
  		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>return unique results</i></div>
  <div color='red' style="font-size:18px;color:red"><i>e.g. RETURN.<b>DISTINCT()</b>.element(b)</i></div>
  <br/>