Evaluate Reverse Polish Notation

1def evalRPN(tokens: List[str]) -> int:
2    stack = []
3    
4    for t in tokens:
5        if t not in {"+", "-", "*", "/"}:
6            stack.append(int(t))
7            continue
8        b = stack.pop()
9        a = stack.pop()
10        if t == "+":
11            stack.append(a + b)
12        elif t == "-":
13            stack.append(a - b)
14        elif t == "*":
15            stack.append(a * b)
16        else:
17            stack.append(int(a / b))
18    
19    return stack[-1]