public function deleteById($id) : int
    {
        $sql = 'DELETE FROM `' . $this->table . '` WHERE ';

        // Assign ids
        if (is_array($id)) {
            $i = 0;
            foreach ($id as $_id) {
                if ($i === 0) {
                    $sql .= ' id=:id' . $i;
                } else {
                    $sql .= ' OR id=:id' . $i;
                }
                $i++;
            }
            $query = $this->pdo->prepare($sql);
            for ($j = 0; $j < 0; $j++) {
                $query->bindParam(':id' . $j, $id[$j]);
            }
        } else {
            $sql .= 'id=:id';
            $query = $this->pdo->prepare($sql);
            $query->bindParam(':id', $id);
        }

        $query->execute();

        return $query->rowCount();
    }