code: def set_transition_down(self, p_self):
          '''Set the downbeat-tracking transition matrix according to
          self-loop probabilities.
  
          Parameters
          ----------
          p_self : None, float in (0, 1), or np.ndarray [shape=(2,)]
              Optional self-loop probability(ies), used for Viterbi decoding
          '''
          if p_self is None:
              self.down_transition = None
          else:
              self.down_transition = transition_loop(2, p_selff set_transition_down(self, p_self):
          '''Set the downbeat-tracking transition matrix according to
          self-loop probabilities.
  
          Parameters
          ----------
          p_self : None, float in (0, 1), or np.ndarray [shape=(2,)]
              Optional self-loop probability(ies), used for Viterbi decoding
          '''
          if p_self is None:
              self.down_transition = None
          else:
              self.down_transition = transition_loop(2, p_self)
docs: Set the downbeat-tracking transition matrix according to
          self-loop probabilities.
  
          Parameters
          ----------
          p_self : None, float in (0, 1), or np.ndarray [shape=(2,)]
              Optional self-loop probability(ies), used for Viterbi decoding