[Zope-CMF] workflow

[Aruna]

Hi!
I have created a workflow through the ZMI. I seem to be having a problem 
assigning /specifying permissions or roles.

I am unable to figure out how if the  multiple roles I specify in the 
transitions tab in the ZMI is actually right.
Should I give them comma seperated or with semicolons?
For eg:
I need to be able to say users "with all the following roles " can 
approve an object

Reader, Writer, Approver.

Do I give

Reader; Writer; Approver
OR
Reader, Writer, Approver
OR
Reader and Writer and Approver

Ty for your time.
AP