already written optparse callback for range and list arguments?

[Alex Gittens]

I would like my program to accept a list of range values on the
command line, like
-a 1
-a 1-10
-a 4,5,2

In the interest of avoiding reinventing the wheel, is there already
available code for a callback that would enable optparse to parse
these as arguments?

Thanks,
Alex
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