Write the function max_int_in_list that takes a list of ints and returns the biggest int in the list. You can assume that the list has at least one int in it. A call to this function would look like: my_list = [5, 2, -5, 10, 23, -21]
biggest_int = max_int_in_list(my_list)
# biggest_int is now 23
Do not use the built-in function max in your program!

Hint: The highest number in the list might be negative! Make sure your function correctly handles that case.