def _load_panel_customization(self):
        """Applies the plugin-based panel configurations.

        This method parses the panel customization from the ``HORIZON_CONFIG``
        and make changes to the dashboard accordingly.

        It supports adding, removing and setting default panels on the
        dashboard. It also support registering a panel group.
        """
        panel_customization = self._conf.get("panel_customization", [])

        # Process all the panel groups first so that they exist before panels
        # are added to them and Dashboard._autodiscover() doesn't wipe out any
        # panels previously added when its panel groups are instantiated.
        panel_configs = []
        for config in panel_customization:
            if config.get('PANEL'):
                panel_configs.append(config)
            elif config.get('PANEL_GROUP'):
                self._process_panel_group_configuration(config)
            else:
                LOG.warning("Skipping %s because it doesn't have PANEL or "
                            "PANEL_GROUP defined.", config.__name__)
        # Now process the panels.
        for config in panel_configs:
            self._process_panel_configuration(config)
Applies the plugin-based panel configurations.

        This method parses the panel customization from the ``HORIZON_CONFIG``
        and make changes to the dashboard accordingly.

        It supports adding, removing and setting default panels on the
        dashboard. It also support registering a panel group.