Is type-pools still necessary?

Hi.

This SAP link says that don't: http://help.sap.com/abapdocu_731/en/abaptype-pools.htm

But I got an error: "ABAB_POOL" type is unknown.

class abap_bool_test definition.
public section.
methods:
test importing b type abap_bool
returning value(result) type string.
endclass.

The error doesn't appear if I declare the type pool: type-pools abap.

Regards,

Leandro.