demo of flask_caching - calculating pi with ζ(2)

flask_caching_demo.py

from flask import Flask
from flask_caching import Cache

app = Flask(__name__)
app.config.from_mapping({"CACHE_TYPE": "simple"})
cache = Cache(app)

def approximate_pi(n):
    output = 0
    for i in range(1, n):
        output += i ** (-2)
    return (6 * output) ** 0.5

@app.route("/<int:n>")
@cache.cached(timeout=50)
def index(n):
    return f'Pi is approximately: {approximate_pi(n)}'