Method: ADD_RELATIONS
Method: INITIALIZE
Method: SET_INIT_FLAG
Method: GET_LOADED_TREE_ELEMENTS
Method: CLEAR_INIT_FLAG
Method: GET_INIT_FLAG
Method: GET_DESCRIPTION
Method: INSERT_NEXT_LEVEL_INTO_TABLES
Method: GET_NEXT_LEVEL
Method: EXIST_INSTANCE
Method: GET_INSTANCE
Method: GET_RELATIONSHIPS