code: def test_preserve_peaks(radius):
      x, y = np.meshgrid(range(100), range(100))
      img = 0 * x + 0 * y + 10
      img[10, 10] = 20
      img[20, 20] = 35
      img[45, 26] = 156
  
      expected_img = img - 10
      background = rolling_ball(img, radius=radius)
      assert np.allclose(img - background, expected_img)
  
file_path: scikit-image/skimage/restoration/tests/test_rolling_ball.py
imports: import numpy
  import pytest
  from skimage import data
  from skimage.restoration._rolling_ball import rolling_ball
  from skimage.restoration._rolling_ball import ellipsoid_kernel
label_desc: Use image node_id 6 for calling a global function with example usage: test_preserve_peaks(radius) without return types