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: javascript_var.rb
    path of file: ./repos/wpscan/lib/wpscan/finders/dynamic_finder/version
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module WPScan
  module Finders
    module DynamicFinder
      module Version
        # Version finder using JavaScript Variable method
        class JavascriptVar < Finders::DynamicFinder::Version::Finder
          # @return [ Hash ]
          def self.child_class_constants
            @child_class_constants ||= super().merge(
              XPATH: '//script[not(@src)]', VERSION_KEY: nil,
              PATTERN: nil, CONFIDENCE: 60
            )
          end

          # @param [ Typhoeus::Response ] response
          # @param [ Hash ] opts
          # @return [ Version ]
          def find(response, _opts = {})
            target.xpath_pattern_from_page(
              self.class::XPATH, self.class::PATTERN, resp
    
          def find(response, _opts = {})
            target.xpath_pattern_from_page(
              self.class::XPATH, self.class::PATTERN, response
            ) do |match_data, _node|
              next unless (version_number = version_number_from_match_data(match_data))

              # If the text to be output in the interesting_entries is > 50 chars,
              # get 20 chars before and after (when possible) the detected version instead
              match = match_data.to_s
              match = match[/.*?(.{,20}#{Regexp.escape(version_number)}.{,20}).*/, 1] if match.size > 50

              return create_version(
                version_number,
                interesting_entries: ["#{response.effective_url}, Match: '#{match.strip}'"]
              )
            end
            nil
          end