code: def _break_signals(self):
          r
          for name in list(self.signals.keys()):
              if self.signals[name].ndim == 2:
                  for i, signal_1d in enumerate(self.signals[name].T):
                      self.signals[name + '_' + str(i)] = signal_1d
                  del self.signals[name]
docs: r"""Break N-dimensional signals into N 1D signals.