code: def _uniform_sample(self):
          
  
          # get a random episode index
          ep_ind = random.choice(self.demo_list)
  
          # select a flattened mujoco state uniformly from this episode
          states = self.demo_file["data/{}/states".format(ep_ind)].value
          state = random.choice(states)
  
          if self.need_xml:
              model_xml = self._xml_for_episode_index(ep_ind)
              xml = postprocess_model_xml(model_xml)
              return state, xml
          return state
docs: Sampling method.
  
          First uniformly sample a demonstration from the set of demonstrations.
          Then uniformly sample a state from the selected demonstration.