code: def trajectories(self, M, N, start=None, stop=None):
          
          trajs = [self.trajectory(N, start=start, stop=stop) for _ in range(M)]
          return trajs
docs: Generates M trajectories, each of length N, starting from state s
  
          Parameters
          ----------
          M : int
              number of trajectories
          N : int
              trajectory length
          start : int, optional, default = None
              starting state. If not given, will sample from the stationary distribution of P
          stop : int or int-array-like, optional, default = None
              stopping set. If given, the trajectory will be stopped before N steps
              once a state of the stop set is reached