A simple python function to reverse a list in place.

reverse_it.py

def reverse_it(arr):
  if not arr:
    return 
  
  high, low = len(arr) - 1 , 0

  while high > low:
    arr[low], arr[high] = arr[high], arr[low]
    high, low = high - 1, low + 1
    
  return arr 
  
a = [1, 2, 3, 4, 5]
b = [ 10, 9, 8, 7, 6]

print(reverse_it(a)) # [5, 4, 3, 2, 1]
print(reverse_it(b)) # [6, 7, 8, 9, 10]
print(reverse_it([1, 2])) # [2, 1]
print(reverse_it([1])) # [1]