Slightly OT, but I think 'break' and 'continue' should be replaced with 'raise Break' and 'raise Continue' in Python 4000, just as we 'raise StopIteration' in generators today. This would be handy, because you could use it in functions called by a list comprehension:
def while(x): if x > 10: raise Break else: return x
[while(x) for x in range(20)] #produces [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Right now, you can do something this with list(generator expression) by raising StopIteration, but it is considered a hack, and it doesn't work with list comprehensions.