code: public IPRangeNode get(InetAddress addr) {
  
  	if (version == 0) // no data was added
  	    return null;
  
  	IPRangeNode node = isV4(addr) ? ipv4 : ipv6;
  
  	if (!this.isSorted) this.optimize();
  
  	return node.findFast(addr);
      }
docs: returns a single, best matching node for the given address
  
  @param addr
  @return