<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _register_dataparser(self, plugin_name, plugin_instance):
 """ Register a parser. :param plugin_name: Parser name :param plugin_instance: PluginBase :return: Nothing """

        for parser in plugin_instance.get_parsers().keys():
            if self.responseparser.has_parser(parser):
                raise PluginException("Parser {} already registered to parsers! Unable to "
                                      "add parsers from {}.".format(parser, plugin_name))
            self.responseparser.add_parser(parser, plugin_instance.get_parsers().get(parser))