public function setValueType($valueType)
    {
        if (in_array($valueType, ParamType::asArray(), true) === true) {
            $this->valueType = $valueType;
        } else {
            $msg = "The 'valueType' argument must be a value from the ParamType enumeration, '" . gettype($valueType) . "' given.";
            throw new InvalidArgumentException($msg);
        }
    }