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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 _insert(self, key, records, count):
 """ Insert records according to key """

        if key not in self.records:
            assert key not in self.counts
            self.records[key] = records
            self.counts[key] = count
        else:
            self.records[key] = np.vstack((self.records[key], records))
            assert key in self.counts
            self.counts[key] += count