CurrentMonth can be calculated by a sql statement.
Note:
REPOSITORY VARIABLE(DYNAMIC)
· Initialized when BI server is started
· Assigned value dynamically based on the result of a query
· Value is dependent of the sql provided in Initialization Block
Create a dynamic variable and provide a Name and Default Initializer.Create a new initialization block by clicking on the New button in the above screen.

Provide Intialization Block variable Name

Click on “Edit Data Source” button and provide the sql to be used for the variable, e.g.
select lower(sys_context('USERENV','SESSION_USER'))||
'@'||
lower(sys_context('USERENV','DB_NAME'))
from dual;