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