code: def test_mask(level):
      # Test missing data via explicit masking
      contours = find_contours(
          a, level, positive_orientation="high", mask=mask
      )
      assert len(contours) == 1
      assert_array_equal(contours[0], mask_contour)
  
file_path: scikit-image/skimage/measure/tests/test_find_contours.py
imports: import numpy
  from skimage.measure import find_contours
  from skimage._shared.testing import assert_array_equal
  import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: test_mask(level) without return types