How to Find the Interval String of an Interval Partition Table

SQL> select TABLE_NAME, PARTITIONING_TYPE, INTERVAL 
     from dba_part_tables 
     where owner='TESTUSER' ;

TABLE_NAME    PARTITION_TYPE    INTERVAL
------------- ----------------- -----------------------------
TABLE1        RANGE             NUMTODSINTERVAL(1, 'DAY' )
TABLE2        RANGE             NUMTODSINTERVAL(1, 'MONTH' )
TABLE3        RANGE             NUMTODSINTERVAL(15, 'MINUTE' )
...
..
.