(data['files'].is_a?(Array) ? data['files'] : []).each do |file_data|
        attributes[:files].push File.new(
          :id => Osm::to_i_or_nil(file_data['fileid']),
          :activity_id => Osm::to_i_or_nil(file_data['activityid']),
          :file_name => file_data['filename'],