code: function put(propName, propValue, classId) {
  	if (pick(propName, propValue)) return false;
  
  	if (!classId) {
  		nextClassId++;
  		classId = nextClassId;
  	}
  
  	nextClassId = nextClassId < classId ? classId : nextClassId;
  
  	storage[propName] = storage[propName] || {};
  	storage[propName][classId] = propValue;
  
  	return true;
  }
docs: sets the classId