Python:检测斐波那契额数列的运算时间？

import time

def fib(n):  #斐波那契数列
    if n in (1, 2):
        return 1
    else:
        return fib(n - 1) + fib(n - 2)

for i in range(1, 35):
    start = time.time()     #时间检测
    f = fib(i)
    end = time.time()
    print(f'fib{i}={f},{end-start:10.7f}seconds')