def modifier=(modifier)
      validator = EnumAttributeValidator.new('String', ["exclude", "include"])
      unless validator.valid?(modifier)
        fail ArgumentError, "invalid value for 'modifier', must be one of #{validator.allowable_values}."
      end
      @modifier = modifier
    end
def modifier=(modifier)
      validator = EnumAttributeValidator.new('String', ["exclude", "include"])
      unless validator.valid?(modifier)
        fail ArgumentError, "invalid value for 'modifier', must be one of #{validator.allowable_values}."
      end
      @modifier = modifier
    end
Custom attribute writer method checking allowed values (enum).
 @param [Object] modifier Object to be assigned