Trying to code a function with one numeric input. If the number <= 0, return -1. If the number > 0, divide that integer over-and-over by 2

Question

I am new to Python and coding. This is what I have so far, but can\'t get it to work.

def halve_to_2( num ): while True: num = num /2 if num < 2: else: if num <