Explanation/Reference:
Explanation:
https://docs.oracle.com/database/121/SQLRF/statements_6014.htm#SQLRF01311
"CONTAINER Clause The CONTAINER clause applies when you are connected to a CDB. However, it is not necessary to specify the CONTAINER clause because its default values are the only allowed values.
To create a common role, you must be connected to the root. You can optionally specify CONTAINER = ALL, which is the default when you are connected to the root. To create a local role, you must be connected to a PDB. You can optionally specify CONTAINER = CURRENT, which is the default when you are connected to a PDB."