Where is the call to Tempfile.new in this code?

At the following URL

There is the following code

require 'ftools'
require 'tempfile'

def compete who, f
  5.times do |i|
    f.flock File::LOCK_EX
    f.puts format("%s:%d @ %f\n",who, i, Time.now.to_f)
    f.flock File::LOCK_UN

path = format(__FILE__ + '.out')
fd = open(path, File::WRONLY | File::TRUNC | File::CREAT)

if fork
  compete 'PARENT', fd

  Process.wait rescue nil
  open(path){|f| puts f.read}
  File.rm_f path if File.exist? path

  compete 'CHILD', fd

The code runs on my system. But, I don't see any call to Tempfile.new.
I'm assuming it's implied? If it is being implied, where is it being
implied at in the code?