def attribute_name=(attribute_name)
      if attribute_name.nil?
        fail ArgumentError, "attribute_name cannot be nil"
      end

      if attribute_name.to_s.length < 1
        fail ArgumentError, "invalid value for 'attribute_name', the character length must be great than or equal to 1."
      end

      @attribute_name = attribute_name
    end
def attribute_name=(attribute_name)
      if attribute_name.nil?
        fail ArgumentError, "attribute_name cannot be nil"
      end

      if attribute_name.to_s.length < 1
        fail ArgumentError, "invalid value for 'attribute_name', the character length must be great than or equal to 1."
      end

      @attribute_name = attribute_name
    end
Custom attribute writer method with validation
 @param [Object] attribute_name Value to be assigned