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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 process_item(self, item):
 """Calculate new maximum value for each group, for "new" items only. """

        group, value = item['group'], item['value']
        if group in self._groups:
            cur_val = self._groups[group]
            self._groups[group] = max(cur_val, value)
        else:
            # New group. Could fetch old max. from target collection,
            # but for the sake of illustration recalculate it from
            # the source collection.
            self._src.tracking = False  # examine entire collection
            new_max = value
            for rec in self._src.query(criteria={'group': group},
                                       properties=['value']):
                new_max = max(new_max, rec['value'])
            self._src.tracking = True  # back to incremental mode
            # calculate new max
            self._groups[group] = new_max