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: classes.rb
    path of file: ./repos/truffleruby/spec/ruby/library/socket/fixtures
    
    the code of the file until where you have to start completion: require 'socket'

module So
    
  def self.ipv6_available?
    @ipv6_available ||= begin
      server = TCPServer.new('::1', 0)
    rescue Errno::EAFNOSUPPORT, Errno::EADDRNOTAVAIL, SocketError
      :no
    else
      server.close
      :yes
    end