code: def test_mask_feature():
      """test_feature_masking"""
      toto = np.random.rand(*shape)
      ddom = domain_from_binary_array(toto)
      ddom.set_feature("data", np.ravel(toto))
      mdom = ddom.mask(np.ravel(toto > 0.5))
      plop = mdom.get_feature("data")
      assert_almost_equal(plop, toto[toto > 0.5])
  
imports: import nibabel.gifti
  import numpy
  from nibabel import Nifti1Image
  from numpy.testing import assert_almost_equal, assert_array_equal
  from ..discrete_domain import domain_from_binary_array, domain_from_image, domain_from_mesh, grid_domain_from_binary_array, grid_domain_from_image, grid_domain_from_shape, smatrix_from_3d_array, smatrix_from_nd_array, smatrix_from_nd_idx
label_desc: Use image node_id 17 for calling a global function with example usage: test_mask_feature() without return types