getValidPlaceholderTypes example

throw $e;
        }

        if (null === $this->handlingPlaceholder || null === $value) {
            $this->validateType($value);

            return;
        }

        $knownTypes = array_keys(self::$placeholders[$this->handlingPlaceholder]);
        $validTypes = $this->getValidPlaceholderTypes();

        if ($validTypes && array_diff($knownTypes, $validTypes)) {
            $e = new InvalidTypeException(sprintf(
                'Invalid type for path "%s". Expected %s, but got %s.',
                $this->getPath(),
                1 === \count($validTypes) ? '"'.reset($validTypes).'"' : 'one of "'.implode('", "', $validTypes).'"',
                1 === \count($knownTypes) ? '"'.reset($knownTypes).'"' : 'one of "'.implode('", "', $knownTypes).'"'
            ));
            if ($hint = $this->getInfo()) {
                $e->addHint($hint);
            }