public function addUnnamedPlaceholderValues(array $placeholderValues) : self
    {
        foreach ($placeholderValues as $value) {
            if (is_array($value)) {
                if (count($value) !== 2) {
                    throw new InvalidQueryException('Incorrect number of items in value array');
                }

                $this->addUnnamedPlaceholderValue($value[0], $value[1]);
            } else {
                $this->addUnnamedPlaceholderValue($value);
            }
        }

        return $this;
    }