Weighted choices

[Jason Friedman]

choices = dict()
choices["apple"] = 10
choices["pear"] = 20
choices["banana"] = 15
choices["orange"] = 25
choices["kiwi"] = 30

I want to pick sets of fruit, three in a set, where the chance of
selecting a given fruit is proportional to its weight.  In the example
above, pears should appear twice as often as apples and kiwis should
appear twice as often as bananas.

I see this solution
(http://stackoverflow.com/questions/3679694/a-weighted-version-of-random-choice)
but it is for single choices at a time.  random.sample() does not
provide a "weight" argument.

I can picture how to write this with many, many lines of code but I
have a feeling there is an elegant solution.