buy route pset7 Finance

@app.route("/buy", methods=["GET", "POST"])
@login_required
def buy():
    """Buy shares of stock."""

    if request.method == "POST":
        # ensure a symbol was submitted
        if not request.form.get("symbol"):
            return apology("symbol required")

        # check if symbol is valid
        stock = lookup(request.form.get("symbol"))
        if not stock:
            return apology("symbol does not exist")

        # ensure that number of shares entered is not negative
        user_input_shares = int(request.form.get("shares"))
        if user_input_shares < 0:
            return apology("number of shares cannot be negative!")

        # check how much cash user has
        users_info = db.execute("SELECT cash FROM users WHERE id=:uid", uid=session["user_id"])
        if not users_info:
            return apology("something went wrong when looking up cash amount")

        # calculate total price of stock
        total = stock["price"] * user_input_shares
        if total > users_info[0]["cash"]:
            return apology("You don't have enough money!")

        # update user's information and total amount of cash in database and send user to Portfolio
        total_cash = users_info[0]["cash"] - total
        db.execute("UPDATE users SET cash=:cash WHERE id=:uid", cash=total_cash, uid=session["user_id"])

        db.execute("INSERT INTO user_stocks (stock_name, stock_price, stock_symbol, no_of_shares, user_id) VALUES(:sname, :sprice, :ssymbol, :shares, :uid)",
        sname=stock["name"], sprice=stock["price"], ssymbol=stock["symbol"], shares=user_input_shares, uid=session["user_id"])

        return redirect(url_for("index"))

    elif request.method == "GET":
        return render_template("buy.html")