Python Reference Model

main.py

from typing import Dict, List

database = {
    "apple": "red",
    "banana": "yellow",
    "cherry": "red"   
}

def fruit_colors() -> List[str]:
    fruit_color_cache: Dict[str, str] = {}

    fruits = ["apple", "banana", "cherry", "cherry", "apple"]

    for fruit in fruits:
        color = fetch_fruit_color(fruit, fruit_color_cache)
        print(f"{fruit} is {color}")

def fetch_fruit_color(fruit: str, cache: Dict[str, str]) -> str:
    if fruit not in cache:
        print(f'>> cache miss for {fruit}')
        cache[fruit] = database[fruit]
    else:
        print(f'>> cache hit for {fruit}')

    return cache[fruit]

fruit_colors()

"""
the output shows that the cache actually gets updated

>> cache miss for apple
apple is red
>> cache miss for banana
banana is yellow
>> cache miss for cherry
cherry is red
>> cache hit for cherry
cherry is red
>> cache hit for apple
apple is red
"""