PSET7 - check 50: 'NoneType' object is not subscriptable

def pulling_portfolio(rows, cash):
    """Creating a searcher to rearrange the transactions into a portfolio"""
    share_cache = []
    """Creating a filtered copy of the list"""
    for i in range(0, len(rows)):
        if len(share_cache) < 1:
            share_cache.append(rows[i].copy())

        else:
            for j in range(0, len(share_cache)):
                if rows[i]["symbol"] == share_cache[j]["symbol"]:
                    break
            else:
                share_cache.append(rows[i].copy())

    '''Setting every quantity to 0 to avoid doubles'''
    for i in range(0, len(share_cache)):
        share_cache[i]["quantity"] = 0

    """Summing the quantity out of the transactions"""
    for i in range(0, len(share_cache)):
        cache = share_cache[i]["symbol"]
        for j in range(0, len(rows)):
            if rows[j]["symbol"] == cache:
                share_cache[i]["quantity"] += rows[j]["quantity"]
    """Adding Price and Value to the list"""
    for i in range(0, len(share_cache)):
        cache = share_cache[i]["symbol"]
        cache_dict = lookup(cache)
        share_cache[i]["price"] = cache_dict["price"]
        share_cache[i]["value"] = float(share_cache[i]["price"]) * float(share_cache[i]["quantity"])

    return share_cache

def buy():
    """Buy shares of stock."""

    if request.method == "POST":
        symbol = request.form.get("symbol")
        try:
            quantity_buy = int(request.form.get("shares"))
        except:
            try:
                quantity_buy = int(request.form.get("shares_buy"))
            except:
                return apology("Please check your input: METHOD Error")
        quote_buy = lookup(symbol)

        if not quote_buy:
            return apology("Yo die Quote geht nicht")

        for key, value in quote_buy.items():
            if isinstance(quote_buy[key], type(None)):
                return apology("Fehler ist im quote_buy")

        user_id = session.get("user_id")

        if not isinstance(quantity_buy, int) or len(symbol) < 1 or quantity_buy < 1:
            return apology("Please check your input: INPUT ERROR")

        elif not quote:
            return apology("Insert a valid symbol")

        try:
            try:
                stock_price = quote_buy["price"] * quantity_buy
                cash_cache = db.execute("SELECT cash FROM users WHERE id = :id", id = user_id)

                if (isinstance(cash_cache[0]["cash"], type(None))):
                    return apology("Fehler ist im cash_cache")

                old_cash = cash_cache[0]["cash"]
                new_cash = old_cash - stock_price
            except:
                return apology("Here is the BUG")

            if new_cash < 0:
                return apology("Sorry you have not enough cash!")

            else:
                try:
                    transaction_completed = db.execute("UPDATE users SET cash = :newcash WHERE id = :sessionid", newcash = new_cash, sessionid = user_id)
                    result = db.execute("INSERT INTO transactions (id, type, symbol, quantity, current_price) VALUES (:id, :type, :quote, :quantity, :current_price)", id = user_id, type = "buy", quote = quote_buy["name"], quantity = quantity_buy, current_price = stock_price *-1)

                except:
                    return apology("Problem mit updaten der DBs")

                if not transaction_completed or not result:
                    return apology("Your transaction could not be finished.")

                else:
                    return redirect(url_for("index"))

        except:
            return apology("Oops, something went wrong")

    else:
        return render_template("buy.html")

@app.route("/index")
@login_required
def index():
    """Show a Dashboard."""
    user_id = session.get("user_id")
    rows = db.execute("SELECT symbol, quantity FROM transactions WHERE id = :uid", uid = user_id)
    cash = db.execute("SELECT cash FROM users WHERE id = :uid", uid = user_id)

    share_cache = pulling_portfolio(rows, cash)

    """Calculating the current value of all the shares"""
    try:
        total = 0
        for i in range(0, len(share_cache)):
            total += share_cache[i]["value"]
            share_cache[i]["price"] = usd(share_cache[i]["price"])
            share_cache[i]["value"] = usd(share_cache[i]["value"])

        total += cash[0]["cash"]

        return render_template("index.html", table_content = share_cache, total = usd(total), total_cash = usd(cash[0]["cash"]))

    except:
        return apology("Your portfolio cannot be displayed")