docs: def score(self, obs, pstates):
          """
          Compute the log probability under the model.
          """
          pstates_idx = np.array([self.e[p] for p in pstates])
          framelogprob = self._compute_log_likelihood(obs, pstates_idx)
          logprob, _ = self._do_forward_pass(framelogprob, pstates_idx)
          return logprob