'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.'

def _load_panel_customization(self):

    panel_customization = self._conf.get('panel_customization', [])
    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__)
    for config in panel_configs:
        self._process_panel_configuration(config)
