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: row.rb
    path of file: ./repos/hitobito/app/domain/export/tabular/events
    
    the code of the file until where you have to start completion: # encoding: utf-8

#  Copyright (c) 2012-2014, Jungwacht Blauring Schweiz. This file is part of
#  hitobito and licensed under the Affero General Public License 
    
    def contactable_attribute(contactable_attr)
      subject, attr = contactable_attr.to_s.split('_', 2)
      contactable = send(subject)
      if contactable
        contact_attr = :"contact_#{attr}"
        if respond_to?(contact_attr, true)
          send(contact_attr, contactable)
        else
          contactable.send(attr)
        end