code: def test_features(self):
      sv_true = pd.DataFrame(
          {
              "color": ["b", "g", "g", "r"],
              "size": [2, 1, 3, 1],
              "n_nodes": [1, 1, 2, 1],
          }
      )
      sv_true.set_index(["color", "size"], inplace=True)
  
      sv_test = g.partition_nodes(["color", "size"])
  
      assert_frame_equal(sv_test, sv_true)
  
imports: import pytest
  import numpy
  import pandas
  from pandas.testing import assert_frame_equal
  from numpy.testing import assert_allclose
  from deepgraph import DeepGraph
label_desc: Use image node_id 5 for calling the TestPartitionNodes obj's underlying member method code with example usage: obj.test_features() without return types