Extract margin formating related subset of widget settings.

def _es_margin(settings):
        """
        Extract margin formating related subset of widget settings.
        """
        return {k: settings[k] for k in (ConsoleWidget.SETTING_MARGIN,
                                         ConsoleWidget.SETTING_MARGIN_LEFT,
                                         ConsoleWidget.SETTING_MARGIN_RIGHT,
                                         ConsoleWidget.SETTING_MARGIN_CHAR)}