programming_book_examples/algorithms/fibonacci/fibonacci_with_lru_cache.py

#!/usr/bin/env python3
from functools import lru_cache


@lru_cache(maxsize = 1000)
def fibonacci(n):
    # check input type. must be positive integer.
    if type(n) != int:
        raise TypeError("n must be a positive int")
    if n < 1:
        raise ValueError("n must be a positive int")

    # compute the nth term
    if n == 1:
        return 1
    elif n == 2:
        return 1
    elif n > 2:
        return fibonacci(n-1) + fibonacci(n-2)


for n in range(1, 501):
    print(n, ":", fibonacci(n))