def attachments
      return @builder.object.send(attribute_name).to_a unless multiple?
      @builder.object.send(attribute_name).sort_by { |a| @builder.object.send(relation_key).index(a.id) }
    end
def attachments
      return @builder.object.send(attribute_name).to_a unless multiple?
      @builder.object.send(attribute_name).sort_by { |a| @builder.object.send(relation_key).index(a.id) }
    end
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