import heapq

class foo:
    def __init__(self):
        self.timeout = 0
    def __le__(self, other):
        return self.timeout <= other.timeout

heap = []
heapq.heappush(heap, foo())
heapq.heappush(heap, foo())


This code on Python 2.x works without problems, by using Python3.0-RC1
it raises the following exception:


    heapq.heappush(heap, foo())
TypeError: unorderable types: foo() < foo()


Note that the previous 3.0 beta didn't have such problem.

heapq expects a _lt_ method, and the error doesn't occur when the _le_
method is changed to _lt. According to the SVN log, this was changed due
to consistency with lists.sort().

It's supposed to be that way.  In 2.6 we support both to help with 
transition. In 3.0, we've cleaned up and made the APIs consistent. Try to 
get in the habit of defining all six rich comparisons to bulletproof code 
and not rely on undocumented implementation details.

Ok, thanks for the hints.