code: def test_is_3dlist():
      assert utils.is_3dlist([])
      assert utils.is_3dlist([[]])
      assert utils.is_3dlist([[[]]])
      assert utils.is_3dlist([[[1]]])
      assert not utils.is_3dlist([[1, 2]])
      assert not utils.is_3dlist([[np.array([1, 2])]])
  
imports: import numpy
  import mmocr.utils
label_desc: Use image node_id 1 for calling a global function with example usage: test_is_3dlist() without return types