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: support_attributes.rb
    path of file: ./repos/closure_tree/lib/closure_tree
    
    the code of the file until where you have to start completion: require 'forwardable'
module ClosureTree
  module SupportAttributes
    extend Forwardable
    d
    
    def order_column
      o = order_by
      if o.nil?
        nil
      elsif o.is_a?(String)
        o.split(' ', 2).first
      else
        o.to_s
      end