code: def _get_samples(self, N, trace_sort):
          this_run = self.samples.append(N)
          if trace_sort:
              this_run[:], origin = self.proposal.propose(N, self.rng, trace=True, shuffle=False)
              return this_run, origin
          else:
              this_run[:] = self.proposal.propose(N, self.rng)
              return this_run