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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 __check_existing(self, row):
 """Check if row exists in table """

        if self.__update_keys is not None:
            key = tuple(row[key] for key in self.__update_keys)
            if key in self.__bloom:
                return True
            self.__bloom.add(key)
            return False
        return False