Programming Exercise $9\mathrm{.}7$

Define a recursive function named insert, that expects an index, an item, and a Lisp$-$like list as arguments. The function returns a list in which the item is inserted at the given index position.

Here is an example of its use:

$>>>$ lyst $=$ buildRange$(1,5)$

$>>>$ lyst

$(12345)$

$>>>$ insert$(2,66,$ lyst$)$ # insert $66$ at position $2$

$(1266345)$

$>>>$ lyst

$(12345)$