old_contents: # Copyright (c) Jupyter Development Team.
  from jupyter_core.paths import jupyter_data_dir
  import subprocess
  import os
  import errno
  
  PEM_FILE = os.path.join(jupyter_data_dir(), 'notebook.pem')
  
  c = get_config()
  c.NotebookApp.ip = os.getenv('INTERFACE', '') or '*'
  c.NotebookApp.port = int(os.getenv('PORT', '') or 8888)
  c.NotebookApp.open_browser = False
  
  # Set a certificate if USE_HTTPS is set to any value
  if 'USE_HTTPS' in os.environ:
      if not os.path.isfile(PEM_FILE):
          # Ensure PEM_FILE directory exists
          dir_name = os.path.dirname(PEM_FILE)
          try:
              os.makedirs(dir_name)
          except OSError as exc: # Python >2.5
              if exc.errno == errno.EEXIST and os.path.isdir(dir_name):
                  pass
              else: raise
          # Generate a certificate if one doesn't exist on disk
          subprocess.check_call(['openssl', 'req', '-new', 
              '-newkey', 'rsa:2048', '-days', '365', '-nodes', '-x509',
              '-subj', '/C=XX/ST=XX/L=XX/O=generated/CN=generated',
              '-keyout', PEM_FILE, '-out', PEM_FILE])
      c.NotebookApp.certfile = PEM_FILE
  
  # Set a password if PASSWORD is set
  if 'PASSWORD' in os.environ:
      from IPython.lib import passwd
      c.NotebookApp.password = passwd(os.environ['PASSWORD'])
      del os.environ['PASSWORD']
new_contents: # Copyright (c) Jupyter Development Team.
  from jupyter_core.paths import jupyter_data_dir
  import subprocess
  import os
  import errno
  import stat
  
  PEM_FILE = os.path.join(jupyter_data_dir(), 'notebook.pem')
  
  c = get_config()
  c.NotebookApp.ip = os.getenv('INTERFACE', '') or '*'
  c.NotebookApp.port = int(os.getenv('PORT', '') or 8888)
  c.NotebookApp.open_browser = False
  
  # Set a certificate if USE_HTTPS is set to any value
  if 'USE_HTTPS' in os.environ:
      if not os.path.isfile(PEM_FILE):
          # Ensure PEM_FILE directory exists
          dir_name = os.path.dirname(PEM_FILE)
          try:
              os.makedirs(dir_name)
          except OSError as exc: # Python >2.5
              if exc.errno == errno.EEXIST and os.path.isdir(dir_name):
                  pass
              else: raise
          # Generate a certificate if one doesn't exist on disk
          subprocess.check_call(['openssl', 'req', '-new', 
              '-newkey', 'rsa:2048', '-days', '365', '-nodes', '-x509',
              '-subj', '/C=XX/ST=XX/L=XX/O=generated/CN=generated',
              '-keyout', PEM_FILE, '-out', PEM_FILE])
          # Restrict access to PEM_FILE
          os.chmod(PEM_FILE, stat.S_IRUSR | stat.S_IWUSR)
      c.NotebookApp.certfile = PEM_FILE
  
  # Set a password if PASSWORD is set
  if 'PASSWORD' in os.environ:
      from IPython.lib import passwd
      c.NotebookApp.password = passwd(os.environ['PASSWORD'])
      del os.environ['PASSWORD']
subject: Set permissions on PEM_FILE, if generated.