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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 update_subtotals(self, current, sub_key):
 """ updates sub_total counts for the class instance based on the current dictionary counts args: ----- current: current dictionary counts sub_key: the key/value to use for the subtotals """


        if not self.sub_counts.get(sub_key):
            self.sub_counts[sub_key] = {}
        for item in current:
            try:
                self.sub_counts[sub_key][item] += 1
            except KeyError:
                self.sub_counts[sub_key][item] = 1