SELECT object_type
FROM dba_objects
WHERE owner = 'SH'
AND object_name = 'CUSTOMERS_DIM';
OBJECT_TYPE
--------------------
DIMENSION
exec dbms_sumvdm.verify_dimension('CUSTOMERS_DIM', 'SH');
*
ORA-00942: table or view does not exist
-- given that this is undocumented it may well be me but I can't say I'm impressed. And lest you think I was looking for the table not the dimension name:
exec dbms_sumvdm.verify_dimension('CUSTOMERS', 'SH');
*
ORA-30478: Specified dimension does not exist
-- so the exception message appear to be internally inconsistent.