upn calculator

upn.py

from operator import add, sub, mul, truediv as div

operations = {"+": add, "-": sub, "*": mul, "/": div}

stack = []

def upn(line):
    for token in line.split():
        if token in operations:
            b, a = stack.pop(), stack.pop()
            stack.append(operations[token](a, b))
        else:
            stack.append(float(token))
    print(round(stack[-1], 4))

while True:
    try: upn(input("> "))
    except EOFError: break