Box\Spout\Writer\Common\Helper\AbstractStyleHelper::hasStyleAlreadyBeenRegistered PHP Method

    protected function hasStyleAlreadyBeenRegistered($style)
    {
        $serializedStyle = $style->serialize();
        // Using isset here because it is way faster than array_key_exists...
        return isset($this->serializedStyleToStyleIdMappingTable[$serializedStyle]);
    }