Begins a new group for this settings instance for the given
        settings.
        
        :param      prefix | <str>

def beginGroup(self, prefix):
        """
        Begins a new group for this settings instance for the given
        settings.
        
        :param      prefix | <str>
        """
        if self._customFormat:
            self._customFormat.beginGroup(prefix)
        else:
            super(XSettings, self).beginGroup(prefix)