How to set condition breakpoints?

[Christopher J. Bottaro]

I have a script with a class in it:
class Class:
        def f(x, y):
                # do something

I start up the debugger like this:
python /usr/lib/python2.3/pdb.py myscript.py

I want to set a conditional breakpoint:
b Class.f, x == 1 and y == 2

...but that doesn't work.  How can I do what I want?

Thank you.