old_contents: import sys
  import os
  import unittest
  import subprocess
  import re
  
  
  class TestExamples(unittest.TestCase):
      """ Test Suite for the included examples"""
  
      def test_ballbeam(self):
          self._test_example("ballbeam", debug=False)
  
      def test_balltube(self):
          self._test_example("balltube", debug=False)
  
      def test_simple_pendulum(self):
          self._test_example("simple_pendulum", debug=False)
  
      def test_pendulum(self):
          self._test_example("pendulum", debug=False)
  
      def test_car(self):
          self._test_example("car", debug=False)
  
      def _test_example(self, name: str, debug=False):
          """
          Run the given example while listening for errors on stdout
  
          Args:
              name(str): Module name of the Example to run
              debug: If True, display all output from stdout. Pretty handy when
                  things take longer.
  
          Raises:
              failureException: If the output contains log entries that mention
                  "- ERROR -".
          """
          print("Testing Example: {}".format(name))
          pattern = re.compile(r"(- ERROR -)")
          script = os.sep.join([os.path.dirname(__file__), "example_runner.py"])
          cmd = [sys.executable, script, name]
  
          with subprocess.Popen(cmd,
                                stdout=subprocess.PIPE,
                                bufsize=1,
                                universal_newlines=True) as proc:
              for line in proc.stdout:
                  if debug:
                      print(line, end="")
                  if pattern.search(line):
                      proc.kill()
                      self.fail(line)
  
          if proc.returncode != 0:
              raise self.failureException("Process terminated with: {}"
                                          "".format(proc.returncode))
  
new_contents: import sys
  import os
  import unittest
  import subprocess
  import re
  
  
  class TestExamples(unittest.TestCase):
      """ Test Suite for the included examples"""
  
      def test_ballbeam(self):
          self._test_example("ballbeam", debug=False)
  
      def test_balltube(self):
          self._test_example("balltube", debug=False)
  
      def test_simple_pendulum(self):
          self._test_example("simple_pendulum", debug=False)
  
      def test_pendulum(self):
          self._test_example("pendulum", debug=False)
  
      def test_car(self):
          self._test_example("car", debug=False)
  
      def test_tanksystem(self):
          self._test_example("tanksystem", debug=False)
  
      def _test_example(self, name: str, debug=False):
          """
          Run the given example while listening for errors on stdout
  
          Args:
              name(str): Module name of the Example to run
              debug: If True, display all output from stdout. Pretty handy when
                  things take longer.
  
          Raises:
              failureException: If the output contains log entries that mention
                  "- ERROR -".
          """
          print("Testing Example: {}".format(name))
          pattern = re.compile(r"(- ERROR -)")
          script = os.sep.join([os.path.dirname(__file__), "example_runner.py"])
          cmd = [sys.executable, script, name]
  
          with subprocess.Popen(cmd,
                                stdout=subprocess.PIPE,
                                bufsize=1,
                                universal_newlines=True) as proc:
              for line in proc.stdout:
                  if debug:
                      print(line, end="")
                  if pattern.search(line):
                      proc.kill()
                      self.fail(line)
  
          if proc.returncode != 0:
              raise self.failureException("Process terminated with: {}"
                                          "".format(proc.returncode))
  
subject: Add tanksystem to TestExamples of TestSuite