code: def test_children():
      """test that we obtain children"""
      sf = simple_forest()
      ch = sf.get_children()
      assert len(ch) == 5
      assert ch[0] == []
      assert ch[1] == []
      assert ch[2] == [0, 1]
      assert ch[3] == []
      assert ch[4] == [2, 3]
  
file_path: nipy/nipy/algorithms/graph/tests/test_forest.py
imports: import numpy
  from ..forest import Forest
label_desc: Use image node_id 4 for calling a global function with example usage: test_children() without return types