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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 fetch(self):
 """Fetch datagram."""

        if self._newflg:
            self._newflg = False
            temp_dtgram = copy.deepcopy(self._dtgram)
            for (bufid, buffer) in self._buffer.items():
                temp_dtgram += self.submit(buffer, bufid=bufid)
            return tuple(temp_dtgram)
        return tuple(self._dtgram)