code: def test_valid_subset(self):
      known_labels = ["A", "B", "C"]
      passed_labels = ["A", "B"]
      arg_name = "true_labels"
  
      actual = skplt.validate_labels(
          known_labels, passed_labels, arg_name
      )
      self.assertEqual(actual, None)
  
imports: from __future__ import absolute_import
  import unittest
  import scikitplot.plotters
  from sklearn.datasets import load_iris
  from sklearn.decomposition import PCA
  import numpy
  import matplotlib.pyplot
label_desc: Use image node_id 2 for calling the TestValidateLabels obj's underlying member method code with example usage: obj.test_valid_subset() without return types