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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def totals(iter, keyfunc, sumfunc):
 """groups items by field described in keyfunc and counts totals using value from sumfunc """

    data = sorted(iter, key=keyfunc)
    res = {}

    for k, group in groupby(data, keyfunc):
        res[k] = sum([sumfunc(entry) for entry in group])

    return res