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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 read(self):
 """Read a line of data from the input source at a time."""

        line = self.trace_file.readline()
        if line == '':
            if self.loop:
                self._reopen_file()
            else:
                self.trace_file.close()
                self.trace_file = None
                raise DataSourceError()

        message = JsonFormatter.deserialize(line)
        timestamp = message.get('timestamp', None)
        if self.realtime and timestamp is not None:
            self._store_timestamp(timestamp)
            self._wait(self.starting_time, self.first_timestamp, timestamp)
        return line + "\x00"