code: def test_feat_getter():
      # 3 nodes with features like [[0, 1], [2, 3], [4, 5], [6, 7]]
      g = _graph((3, 4, 2))
      single, several = _feat_getters(g)
  
      np.testing.assert_array_equal(
          single(1), [[2, 3], [10, 11], [18, 19]]
      )
      np.testing.assert_array_equal(
          several(1, 2), [[[2, 3]], [[10, 11]], [[18, 19]]]
      )
      np.testing.assert_array_equal(
          several(1, 3),
          [
              [[2, 3], [4, 5]],
              [[10, 11], [12, 13]],
              [[18, 19], [20, 21]],
          ],
      )
  
file_path: stellargraph/tests/mapper/test_sliding.py
imports: import numpy
  import pytest
  from stellargraph import StellarGraph
  from stellargraph.mapper import SlidingFeaturesNodeGenerator, SlidingFeaturesNodeSequence
  from ..test_utils.graphs import example_graph, example_hin_1
label_desc: Use image node_id 5 for calling a global function with example usage: test_feat_getter() without return types