converting a list of integers into range in python

Question

Is there something existing in python that can convert an increasing list of integers into a range list

E.g. given the set {0, 1, 2, 3, 4, 7, 8, 9, 11} I want to get

Answer 1

I think the other answers are hard to understand, and probably inefficient. Hope this is easier and faster.

def ranges(ints):
    ints = sorted(set(ints))
    range_start = previous_number = ints[0]
    for number in ints[1:]:
        if number == previous_number + 1:
            previous_number = number
        else:
            yield range_start, previous_number
            range_start = previous_number = number
    yield range_start, previous_number