old_contents: """Package reserved for tests and test utilities."""
  
  from __future__ import absolute_import
  
  import unittest
  
  
  def suite():
      """Gather all the tests from this package in a test suite."""
      import tests.unit
      import tests.functional
  
      test_suite = unittest.TestSuite()
      test_suite.addTest(tests.unit.suite())
      test_suite.addTest(tests.functional.suite())
      return test_suite
  
  if __name__ == '__main__':
      unittest.main(defaultTest='suite')
  
new_contents: #! /usr/bin/env python
  
  """Package reserved for tests and test utilities."""
  
  from __future__ import absolute_import
  
  import unittest
  
  
  def suite():
      """Gather all the tests from this package in a test suite."""
      import tests.unit
      import tests.functional
  
      test_suite = unittest.TestSuite()
      test_suite.addTest(tests.unit.suite())
      test_suite.addTest(tests.functional.suite())
      return test_suite
  
  if __name__ == '__main__':
      unittest.main(defaultTest='suite')
  
subject: Add shebang.