public function create(string $className)
    {
        if (array_key_exists($className, $this->cache)) {
            return $this->cache[$className];
        }

        if (!class_exists($className)) {
            throw new RuntimeException("Mapper not found. Attempted to load '{$className}'.");
        }

        $instance = new $className($this->connection, $this->table);
        $this->cache[$className] = $instance;

        return $instance;
    }