code: def test_getchannel(self):
      im = hopper("YCbCr")
      Y, Cb, Cr = im.split()
  
      assert_image_equal(Y, im.getchannel(0))
      assert_image_equal(Y, im.getchannel("Y"))
      assert_image_equal(Cb, im.getchannel(1))
      assert_image_equal(Cb, im.getchannel("Cb"))
      assert_image_equal(Cr, im.getchannel(2))
      assert_image_equal(Cr, im.getchannel("Cr"))
  
imports: import io
  import os
  import shutil
  import sys
  import tempfile
  import pytest
  from PIL import Image, ImageDraw, ImagePalette, UnidentifiedImageError
  from .helper import assert_image_equal, assert_image_equal_tofile, assert_image_similar_tofile, assert_not_all_same, hopper, is_win32, mark_if_feature_version, skip_unless_feature
label_desc: Use image node_id 22 for calling the TestImage obj's underlying member method code with example usage: obj.test_getchannel() without return types