how to make format operator % work with unicode as expected

[Peter Pei]

I am using things like "%-20s%-60s%-10s" in tkinter listbox to make it look 
like a table, with mono sized font like lucie system. But this does not work 
with data contains "Les misérables", because it is unicode, and one byte is 
not neccessary one character. Now how can I resolve this issue?

My issue is "how to make format operator % work with unicode as expected", 
and has nothing to do with tkinter. If I want to use a table widget or 
something, I can. But that's not the question.