Write a recursive function to flatten a nested list of integers, where each element in the list can be either an integer or another list. The function should return a single list of integers.

Example:

Input: $[1,2,[3,4],5,[6,17,8]7]$

Output: $1,2,3,4,5,6,7,8$

Constructs:

You can use the following constructs in your solution:

If$-$else statements

recursive function calls

a list comprehensions

appendi$)$ method

isinstancel$)$ function

You cannot use any loops $($e$.$g$.,$ for, while$)$ in your solution.

def flatten$($listl:

# Your impiementation goes here

pass