'SavePoint' do not work in NPoco(Oracle) for separate execute statements

Question

I'm trying to use NPoco + Oracle + SavePoint. But when I'm trying to rollback savepoint, it throws exception.

Example:

NPoko.IDatabase db = new ...
db.Execute("SAVEPOINT ABC");
db.Execute("ROLLBACK TO SAVEPOINT ABC");

Exception: "ORA-01086: savepoint 'ABC' never established in this session or is invalid"

I need to call 'savepoint' then call some other methods and then rollback or commit.

Thank you.