code: public boolean removeOperand(QueryNode operand) {
          if (operands == null) {
              return false;
          }
          // JCR-1650 search the operand without relying on Object#equals(Object)
          Iterator<QueryNode> it = operands.iterator();
          while (it.hasNext()) {
              if (it.next() == operand) {
                  it.remove();
                  return true;
              }
          }
          return false;
      }
docs: Removes an <code>operand</code> (child node) from this query node.
  
  @param operand the child to remove.
  @return <code>true</code> if the operand was in the list of child nodes
  and has been removed; <code>false</code> if this node does not contain
  <code>operand</code> as a child node.