public function insertStmts(array $stmts, $offset = 0, $remove = 0)
    {
        if (false === $offset) {
            $offset = count($this->stmts);
        } elseif (false === $remove) {
            $remove = count($this->stmts);
        }
        array_splice($this->stmts, $offset, $remove, $stmts);
        return $this;
    }