code: def test_determinant_zero2():
      img = np.zeros((128, 28), np.uint8)
      points = surf(img, threshold=0.0)
      assert type(points) == np.ndarray
  
imports: import mahotas
  import numpy
  from mahotas.features.surf import surf
  from os import path
label_desc: Use image node_id 2 for calling a global function with example usage: test_determinant_zero2() without return types