code: def _check_example(example, n_point=None, no_visible=False):
      assert len(example) >= 2, (
          "Each example must have at least two elements:"
          "img, point (visible is optional)."
      )
  
      if len(example) == 2 or no_visible:
          img, point = example[:2]
          visible = None
      elif len(example) >= 3:
          img, point, visible = example[:3]
  
      assert_is_image(img, color=True)
      assert_is_point(point, visible, img.shape[1:], n_point)
  
imports: import numpy
  import six
  from chainercv.utils.testing.assertions.assert_is_image import assert_is_image
  from chainercv.utils.testing.assertions.assert_is_point import assert_is_point
label_desc: Use image node_id 2 for calling a global function with example usage: _check_example(example, n_point, no_visible) without return types