def set_s_vol(self, vol=None, relative=False):
        '''
        Set the volume of all sounds. If @vol != None, It will be changed to 
        it (or by it, if @relative is True.)
        '''
        if vol != None:
            if relative:
                vol += self.s_vol
            self.s_vol = min(max(vol, 0), 1)
        for sgroup in self.sounds.values():
            for snd in sgroup.values():
                snd.set_volume()
def set_s_vol ( self , vol = None , relative = False ) : if vol != None : if relative : vol += self . s_vol self . s_vol = min ( max ( vol , 0 ) , 1 ) for sgroup in self . sounds . values ( ) : for snd in sgroup . values ( ) : snd . set_volume ( )
Set the volume of all sounds. If @vol != None, It will be changed to 
        it (or by it, if @relative is True.)