[Zope] dictionary definition and strings

[p.t.]

Hi,
as a newbie to Zope and this list, I have a simple question I can't manage 
to get an answer.
If, in a python script, I have a string ="{'aKey':'aValue'}" and I want to 
generate a dictionary from such a string, what should I do?
BTW, the function dict() does not work (at least in Zope 2.4.3)
TIA for any suggestion,
	p.t.