def relation
      return unless @builder
      return unless @builder.object
      return unless @builder.object.relations
      relation = @builder.object.relations[attribute_name.to_s]
      raise "Relation #{attribute_name} not found" unless relation
      relation
    end
def relation
      return unless @builder
      return unless @builder.object
      return unless @builder.object.relations
      relation = @builder.object.relations[attribute_name.to_s]
      raise "Relation #{attribute_name} not found" unless relation
      relation
    end
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