[Zope-DB] getUserName()

[miss]

I am something of a newbie on zope.
Have been attempting to use the getUserName()  object with a python script.
My aim is to pass this result to a transaction file on Postgres.
I seem to have missed something here as the Zope Book is not specific on this 
type of operation.
Will appreciate it if someone can give me some direction on this, or direct me 
to some suitable reading.

Regards
Max Wood