[Zope] Assigning One dtml-var to Another

Hi; I have a dtml-var called *select-blueline* It reads thus: <dtml-var expr="_.whrandom.choice(images.bluelines.objectValues(['DTML Method']))"> I need to be able to assign the value generated from this method to ANOTHER method that I can call. In other words... <dtml-var x> = <dtml-var select-blueline> Then later call <dtml-var x> How do I do this? TIA, BenO