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: template.rb
    path of file: ./repos/wongi-engine/lib/wongi-engine
    
    the code of the file until where you have to start completion: module Wongi::Engine
  Template = Struct.new(:subject, :predicate, :object) do
    def self.variable?(thing)
      thing.is_a?(S
    
    def =~(template)
      case template
      when Template
        (template.subject == :_ || template.subject == subject) &&
          (template.predicate == :_ || template.predicate == predicate) &&
          (template.object == :_ || template.object == object)
      else
        raise Error, "templates can only match other templates"
      end