def _process_execute_error(self, msg):
        """ Process a reply for an execution request that resulted in an error.
        """
        content = msg['content']
        # If a SystemExit is passed along, this means exit() was called - also
        # all the ipython %exit magic syntax of '-k' to be used to keep
        # the kernel running
        if content['ename']=='SystemExit':
            keepkernel = content['evalue']=='-k' or content['evalue']=='True'
            self._keep_kernel_on_exit = keepkernel
            self.exit_requested.emit(self)
        else:
            traceback = ''.join(content['traceback'])
            self._append_plain_text(traceback)
Process a reply for an execution request that resulted in an error.