old_contents: #!/usr/bin/env python
  
  """Computational environment check script for 2014 SciPy Conference Tutorial:
  Reproducible Research: Walking the Walk.
  
  https://github.com/reproducible-research/scipy-tutorial-2014
  """
  
  import sys
  import subprocess
  
  
  return_value = 0
  
  required_packages = ['numpy', 'scipy', 'matplotlib', 'SimpleITK']
  for package in required_packages:
      print('Importing ' + package + ' ...')
      try:
          __import__(package, globals(), locals(), [], 0)
      except ImportError:
          print('Error: could not import ' + package)
          return_value += 1
  
  
  required_executables = ['git', 'dexy', 'ipython', 'nosetests']
  for executable in required_executables:
      print('Executing ' + executable + ' ...')
      try:
          output = subprocess.check_output([executable, '--help'])
      except OSError:
          print('Error: could not execute ' + executable)
          return_value += 1
  
  
  if return_value is 0:
      print('\nSuccess.')
  else:
      print('\nAn error was found in your environment, please see the messages ' +
            'above.')
  sys.exit(return_value)
  
new_contents: #!/usr/bin/env python
  
  """Computational environment check script for 2014 SciPy Conference Tutorial:
  Reproducible Research: Walking the Walk.
  
  https://github.com/reproducible-research/scipy-tutorial-2014
  """
  
  import sys
  import subprocess
  
  
  return_value = 0
  
  required_packages = ['numpy', 'scipy', 'matplotlib', 'SimpleITK']
  for package in required_packages:
      print('Importing ' + package + ' ...')
      try:
          __import__(package, globals(), locals(), [], 0)
      except ImportError:
          print('Error: could not import ' + package)
          return_value += 1
  
  
  print('')
  required_executables = ['git', 'dexy', 'ipython', 'nosetests', 'ffmpeg']
  for executable in required_executables:
      print('Executing ' + executable + ' ...')
      try:
          output = subprocess.check_output([executable, '--help'],
                                           stderr=subprocess.STDOUT)
      except OSError:
          print('Error: could not execute ' + executable)
          return_value += 1
  
  
  if return_value is 0:
      print('\nSuccess.')
  else:
      print('\nAn defect was found in your environment, please see the messages ' +
            'above.')
  sys.exit(return_value)
  
subject: Add ffmpeg to the required environment.