How to Cache API once per 15 minutes

Question

OK, I've been looking at caching examples and not sure how to put this together for my Flask Python Application

I have an object that handles the API request, this is market_data.py

I have a main.py this contains my flask app|

What I would like to do is the following:

1. When the home page is loaded it will check if a cache is available of the API call from market_data.py

2. If the home_page has a cache that is less than 15minutes old I want the flask app to render_template using the cache.

3. IF the cache is older than 15mins I want the home_page to render_template using a new API request.

MarketData.py handles the API request and sends the data to main.py to be rendered by flask for the index.html

Should I cache in the main.py or in the MarketData.py

I'm having trouble understanding how caching works... thank you in advanced

main.py

from flask import Flask, render_template
from flask_caching import Cache
from flask_bootstrap import Bootstrap
from flask_ckeditor import CKEditor
from datetime import date
from market_data import MarketData
import os

current_year = date.today().year
data = MarketData()

cache = Cache(config={'CACHE_TYPE': 'SimpleCache'})
app = Flask(__name__)
cache.init_app(app)

app.config['SECRET_KEY'] = os.environ.get('SECRET_KEY')
ckeditor = CKEditor(app)
Bootstrap(app)


@app.route('/', methods=['GET', 'POST'])
@cache.cached(timeout=50)
def home_page():
    data.get_data()
    return render_template("index.html",
                           year=current_year,
                           count="{:,.0f}".format(data.total_active),
                           total="{:,.2f}".format(data.total_market_cap),
                           per_symbool="{:,.2f}".format(cdata.value_per_ticker),
                           per_all_ticker="{:,.2f}".format(cdata.value_per_all_asset),
                           new_asset="{:,}".format(data.total_active),
                           country="{:,.2f}".format(country),
                           all_value="{:,}".format(data.total_value),
                           time_stamp = data.time_stamp
                           )

if __name__ == "__main__":
    app.run(debug=True)