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