code: def test_auc_exception(self):
      test = self.test.copy()
      l = len(test)
      test["target"] = (
          test["target"]
          .head(l - 10)
          .append(tc.SArray(["unknown"] * 10))
      )
      self.assertRaises(
          ToolkitError, lambda: self._run_test(self.train, test, "auc")
      )
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import turicreate
  from turicreate.toolkits._main import ToolkitError
  import random
label_desc: Use image node_id 2 for calling the MultiClassTreeClassifierTrackingMetricsTest obj's underlying member method code with example usage: obj.test_auc_exception() without return types