[Zope] Test whether ZClass lines type property is empty

ZClass "lines" type property is a "list" in Python. If there are no values, it should render IMHO as an empty list in Python: [] But it renders as a list containing single item. Something like: [""] Consequently, len(variable) is 1, whether there is one line or no lines. I cannot use <dtml-if "_.len(variable)>0"> to see if there are values. How can I discover if the list is empty without computationally expensive constructs? -- Milos Prudek