code: def track_list(self,*args):
          '''
          return the list of tracks contained if the dataset
          '''
          noargs = len(args) == 0
          return np.unique(self.track) if noargs else np.unique(self.track.compress(args[0])f track_list(self,*args):
          '''
          return the list of tracks contained if the dataset
          '''
          noargs = len(args) == 0
          return np.unique(self.track) if noargs else np.unique(self.track.compress(args[0]))
docs: return the list of tracks contained if the dataset