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: document.rb
    path of file: ./repos/shale/lib/shale/adapter/nokogiri
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Shale
  module Adapter
    module Nokogiri
      # Wrapper around Nok
    
        def initialize(version = nil)
          ver = nil
          ver = version if version.is_a?(String)

          @doc = ::Nokogiri::XML::Document.new(ver)
          @namespaces = {}
        end