code: def _check_example(example, n_fg_class):
      assert len(example) >= 3, (
          "Each example must have at least three elements:"
          "img, bbox and label."
      )
  
      img, bbox, label = example[:3]
  
      assert_is_image(img, color=True)
      assert_is_bbox(bbox, size=img.shape[1:])
  
      assert isinstance(
          label, np.ndarray
      ), "label must be a numpy.ndarray."
      assert (
          label.dtype == np.int32
      ), "The type of label must be numpy.int32."
      assert label.shape[1:] == (), "The shape of label must be (*,)."
      assert len(label) == len(
          bbox
      ), "The length of label must be same as that of bbox."
      if len(label) > 0:
          assert (
              label.min() >= 0 and label.max() < n_fg_class
          ), "The value of label must be in [0, n_fg_class - 1]."
  
imports: import numpy
  import six
  from chainercv.utils.testing.assertions.assert_is_bbox import assert_is_bbox
  from chainercv.utils.testing.assertions.assert_is_image import assert_is_image
label_desc: Use image node_id 2 for calling a global function with example usage: _check_example(example, n_fg_class) without return types