code: def _load_poses(self):
          
          pose_file = os.path.join(self.pose_path, self.sequence + '.txt')
  
          # Read and parse the poses
          poses = []
          try:
              with open(pose_file, 'r') as f:
                  lines = f.readlines()
                  if self.frames is not None:
                      lines = [lines[i] for i in self.frames]
  
                  for line in lines:
                      T_w_cam0 = np.fromstring(line, dtype=float, sep=' ')
                      T_w_cam0 = T_w_cam0.reshape(3, 4)
                      T_w_cam0 = np.vstack((T_w_cam0, [0, 0, 0, 1]))
                      poses.append(T_w_cam0)
  
          except FileNotFoundError:
              print('Ground truth poses are not available for sequence ' +
                    self.sequence + '.')
  
          self.poses = poses
docs: Load ground truth poses (T_w_cam0) from file.