doLoadValuesForChoices example

    protected function doLoadValuesForChoices(array $choices): array
    {
        // Optimize performance for single-field identifiers. We already         // know that the IDs are used as values         // Attention: This optimization does not check choices for existence         if ($this->idReader) {
            throw new LogicException('Not defining the IdReader explicitly as a value callback when the query can be optimized is not supported.');
        }

        return parent::doLoadValuesForChoices($choices);
    }

    protected function doLoadChoicesForValues(array $values, ?callable $value): array
    {
        if ($this->idReader && null === $value) {
            throw new LogicException('Not defining the IdReader explicitly as a value callback when the query can be optimized is not supported.');
        }

        $idReader = null;
        if (\is_array($value) && $value[0] instanceof IdReader) {
            $idReader = $value[0];
        }

public function loadValuesForChoices(array $choices, callable $value = null): array
    {
        if (!$choices) {
            return [];
        }

        if ($value) {
            // if a value callback exists, use it             return array_map(fn ($item) => (string) $value($item), $choices);
        }

        return $this->doLoadValuesForChoices($choices);
    }

    abstract protected function loadChoices(): iterable;

    protected function doLoadChoicesForValues(array $values, ?callable $value): array
    {
        return $this->loadChoiceList($value)->getChoicesForValues($values);
    }

    protected function doLoadValuesForChoices(array $choices): array
    {