code: def test_frame_instance(self):
      df = pdml.ModelFrame(datasets.load_digits())
      self.assertIsInstance(df, pdml.ModelFrame)
  
      train_df, test_df = df.model_selection.train_test_split()
  
      self.assertIsInstance(train_df, pdml.ModelFrame)
      self.assertIsInstance(test_df, pdml.ModelFrame)
      self.assertIsInstance(train_df.iloc[:, 2:3], pdml.ModelFrame)
  
imports: import pytest
  import datetime
  import warnings
  import numpy
  import pandas
  import sklearn.datasets
  import sklearn.svm
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 1 for calling the TestModelFrameMultiTarges obj's underlying member method code with example usage: obj.test_frame_instance() without return types