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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 begin(self):
 """Begins a transaction. This method is called automatically when entering a with statement, however it can be called explicitly if you don't want to use a context manager. :raises: :class:`~exceptions.ValueError` if the transaction has already begun. """

        super(Transaction, self).begin()
        try:
            response_pb = self._client._datastore_api.begin_transaction(self.project)
            self._id = response_pb.transaction
        except:  # noqa: E722 do not use bare except, specify exception instead
            self._status = self._ABORTED
            raise