old_contents: #!/usr/bin/env python
  
  """
  Run all mininet core tests
   -v : verbose output
   -quick : skip tests that take more than ~30 seconds
  """
  
  import unittest
  import os
  import sys
  from mininet.util import ensureRoot
  from mininet.clean import cleanup
  from mininet.log import setLogLevel
  
  def runTests( testDir, verbosity=1 ):
      "discover and run all tests in testDir"
      # ensure root and cleanup before starting tests
      ensureRoot()
      cleanup()
      # discover all tests in testDir
      testSuite = unittest.defaultTestLoader.discover( testDir )
      # run tests
      unittest.TextTestRunner( verbosity=verbosity ).run( testSuite )
  
  if __name__ == '__main__':
      setLogLevel( 'warning' )
      # get the directory containing example tests
      testDir = os.path.dirname( os.path.realpath( __file__ ) )
      verbosity = 2 if '-v' in sys.argv else 1
      runTests( testDir, verbosity )
  
new_contents: #!/usr/bin/env python
  
  """
  Run all mininet core tests
   -v : verbose output
   -quick : skip tests that take more than ~30 seconds
  """
  
  from unittest import defaultTestLoader, TextTestRunner
  import os
  import sys
  from mininet.util import ensureRoot
  from mininet.clean import cleanup
  from mininet.log import setLogLevel
  
  def runTests( testDir, verbosity=1 ):
      "discover and run all tests in testDir"
      # ensure root and cleanup before starting tests
      ensureRoot()
      cleanup()
      # discover all tests in testDir
      testSuite = defaultTestLoader.discover( testDir )
      # run tests
      TextTestRunner( verbosity=verbosity ).run( testSuite )
  
  if __name__ == '__main__':
      setLogLevel( 'warning' )
      # get the directory containing example tests
      testDir = os.path.dirname( os.path.realpath( __file__ ) )
      verbosity = 2 if '-v' in sys.argv else 1
      runTests( testDir, verbosity )
  
subject: Fix pylint error