Sort Stack in ascdending order as more stacks increase by value, with Lowest value at top

stack_sort.py

"""Lowest value at top, highest on top."""

from Stack import MyStack


def sort_stack(stack):
    if not stack.is_empty():    
        top_val = stack.pop()
        sort_stack(stack)
        _insert(stack, top_val)
    return stack

def _insert(stack, top_val):
    if not stack.is_empty() and top_val > stack.top():
        temp = stack.pop()
        _insert(stack, top_val)
        top_val = temp
    stack.push(top_val)