code: def set_m_vol(self, vol=None, relative=False):
          '''
          Set the music volume. If @vol != None, It will be changed to it (or by 
          it, if @relative is True.)
          '''
          if vol != None:
              if relative:
                  vol += self.m_vol
              self.m_vol = min(max(vol, 0), 1)
          pygame.mixer.music.set_volume(self.m_volf set_m_vol(self, vol=None, relative=False):
          '''
          Set the music volume. If @vol != None, It will be changed to it (or by 
          it, if @relative is True.)
          '''
          if vol != None:
              if relative:
                  vol += self.m_vol
              self.m_vol = min(max(vol, 0), 1)
          pygame.mixer.music.set_volume(self.m_vol)
docs: Set the music volume. If @vol != None, It will be changed to it (or by 
          it, if @relative is True.)