+ @property
+ def master_gain(self):
+ return gain(self.master_volume)
+
+ def set_master_volume(self, value, delta=False):
+ [db_gain, self.master_volume] = gain(
+ value + int(delta) * self.master_volume,
+ self.master_volume)
+
+ for music in self.open_files.values():
+ music.set_gain(db_gain)