old_contents: from sys import maxsize
  import os
  
  # There is similar code in ./debian/postinst. If you are changing this
  # you probably want to change that too.
  def download_xflux():
      # Determines which is the appropriate executable for 32-bit
      if maxsize == 2147483647:
          print "Downloading 32-bit xflux ..."
          url = "https://justgetflux.com/linux/xflux-pre.tgz"
      elif maxsize == 9223372036854775807:
          print "Downloading 64-bit xflux ..."
          url = "https://justgetflux.com/linux/xflux64.tgz"
      tarchive = "/tmp/xflux.tgz"
      os.system("wget '%s' -O'%s'" % (url, tarchive))
      os.system("tar -xvf '%s'" % tarchive)
  
  if __name__ == '__main__':
      download_xflux()
  
new_contents: from sys import maxsize
  import os
  
  # There is similar code in ./debian/postinst. If you are changing this
  # you probably want to change that too.
  def download_xflux():
      # Determines which is the appropriate executable for 32-bit
      if maxsize == 2147483647:
          print("Downloading 32-bit xflux ...")
          url = "https://justgetflux.com/linux/xflux-pre.tgz"
      elif maxsize == 9223372036854775807:
          print("Downloading 64-bit xflux ...")
          url = "https://justgetflux.com/linux/xflux64.tgz"
      tarchive = "/tmp/xflux.tgz"
      os.system("wget '%s' -O'%s'" % (url, tarchive))
      os.system("tar -xvf '%s'" % tarchive)
  
  if __name__ == '__main__':
      download_xflux()
  
subject: Make download script work with Python 3.