[Zope] calling Python Script from dtml-let

I have a simple Python Script called passwordRandom(). It works fine if I call it with: <dtml-call "REQUEST.set('password', passwordRandom())"> But I want that value to be available for some other things, so I want to set a variable with dtml-let. But if I do: <dtml-let password2 = "passwordRandom()"> (with a </dtml-let> further down) Then I get invalid parameter: "password = "passwordRandom()"", for tag <dtml-let password = "passwordRandom()">, on line 18 of ActivateAccountHack What stupid mistake am I making?