You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: keygen.rb
    path of file: ./repos/mechanize/lib/mechanize/form
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
##
# This class represents a keygen (public / private key generator) found in a
# 
    
  def generate_key(key_size = 2048)
    # Spec at http://dev.w3.org/html5/spec/Overview.html#the-keygen-element
    @key = OpenSSL::PKey::RSA.new key_size
    @spki.public_key = @key.public_key
    @spki.sign @key, OpenSSL::Digest::MD5.new
    self.value = @spki.to_pem
  end