code: def test_assert_is_image(self):
      if self.valid:
          assert_is_image(self.img, self.color, self.check_range)
      else:
          with self.assertRaises(AssertionError):
              assert_is_image(self.img, self.color, self.check_range)
  
imports: import numpy
  import unittest
  from chainercv.utils import assert_is_image
  from chainercv.utils import testing
label_desc: Use image node_id 1 for calling the TestAssertIsImage obj's underlying member method code with example usage: obj.test_assert_is_image() without return types