code: public Tree clear(String path) {
  		Tree child = getChild(path, false);
  		if (child == null) {
  			child = putMap(path);
  		} else {
  			child.clear();
  		}
  		return child;
  	}
docs: Clears the sub-nodes on the specified path. If no matching node exists,
  creates a new empty node. Sample code:<br>
  <br>
  Tree array = node.clear("a.b").add(1).add(2);
  
  @param path
  path of the sub-node
  
  @return the empty sub-node at the specified position