code: def restrict_to_test_data(self):
      smoke_data = [
          dict(
              split=Split(part1=[2, 3], part2=[0, 1, 4]),
              subset={0, 1, 2},
              expected=Split(part1=[0, 1], part2=[2]),
          ),
          dict(
              split=Split(part1=[0, 1, 2, 3, 4, 5], part2=[6]),
              subset={0},
              expected=Split(part1=[], part2=[0]),
          ),
      ]
  
      return self.generate_tests(smoke_data)
  
imports: import random
  import geomstats.backend
  from geomstats.geometry.stratified.wald_space import Split, Topology, Wald, WaldSpace
  from geomstats.test.data import TestData
  from geomstats.test.test_case import np_backend
  from .point_set import PointSetTestData, PointTestData
label_desc: Use image node_id 1 for calling the SplitTestData obj's underlying member method code with example usage: obj.restrict_to_test_data() and returns: self