<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _decode_bytes(self, bytestring):
 """ Internal method used to convert the utf-8 encoded bytestring into unicode. If the conversion fails, the socket will be closed. """

        if not bytestring:
            return u''
        try:
            return bytestring.decode('utf-8')
        except UnicodeDecodeError:
            self.close(1007)
            raise