Given the following program has one error. Write down which line gives the error?

$1.$ def X$($n$1,$ n$2)$:

$2.$ if n$1<$ n$2$:

$3.$ result $=$ n$1$

$4.$ else:

$5.$ result $=$ n$2$

$6.$

$7.$ return result

$8.$

$9.$ def main$()$:

$10.$ k $=$ X$()$

$11.$ print$($k$)$

$12.$

$13.$ main$()$