What does dbms_transform.compute_transformation do?

In 10gR2 (first available in 9.0.1) if you

Describe dbms_transform

it shows a procedure compute_transformation not listed in the documentation. Google searches show it's undocumented... d'uh.

Has anyone explored what this does?

PROCEDURE COMPUTE_TRANSFORMATION
 Argument Name                  Type                    In/Out
 ------------------------------ ----------------------- ------
 MESSAGE                        STANDARD                IN    
 TRANSFORMATION_SCHEMA          VARCHAR2                IN    
 TRANSFORMATION_NAME            VARCHAR2                IN    
 TRANSFORMED_MESSAGE            STANDARD                OUT

From stackoverflow

• An example of AQ dbms_transform: Oracle Streams AQ

  Regards K