code: def _proper_euler_conventions(self):
      letterpairs = itertools.permutations("XYZ", 2)
      return (l0 + l1 + l0 for l0, l1 in letterpairs)
  
imports: import itertools
  import math
  import unittest
  from distutils.version import LooseVersion
  from typing import Optional, Union
  import numpy
  import torch
  from pytorch3d.transforms.rotation_conversions import axis_angle_to_matrix, axis_angle_to_quaternion, euler_angles_to_matrix, matrix_to_axis_angle, matrix_to_euler_angles, matrix_to_quaternion, matrix_to_rotation_6d, quaternion_apply, quaternion_multiply, quaternion_to_axis_angle, quaternion_to_matrix, random_quaternions, random_rotation, random_rotations, rotation_6d_to_matrix
  from .common_testing import TestCaseMixin
label_desc: Use image node_id 6 for calling the TestRotationConversion obj's underlying member method code with example usage: obj._proper_euler_conventions() and returns: unknown