new_contents: #!/usr/bin/env python
  import binascii
  import os
  
  def random_hex(nb):
          return binascii.hexlify(os.urandom(nb)).decode('ascii')
  
  with open('jupyterhub.env', 'w') as f:
      f.write('JPY_COOKIE_SECRET=%s\n' % random_hex(1024))
      f.write('CONFIGPROXY_AUTH_TOKEN=%s\n' % random_hex(64))
  
subject: Add script to generate jupyterhub secret vars.