code: def test_invalid_two_missing(self):
      known_labels = ["A", "B", "C"]
      passed_labels = ["A", "E", "B", "D"]
      arg_name = "true_labels"
  
      with self.assertRaises(ValueError) as context:
          skplt.validate_labels(known_labels, passed_labels, arg_name)
  
      msg = "The following labels were passed into true_labels, but were not found in labels: E, D"
      self.assertEqual(msg, str(context.exception))
  
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 6 for calling the TestValidateLabels obj's underlying member method code with example usage: obj.test_invalid_two_missing() without return types