Find the month with the lowest average price

best_month = min(monthly_average_prices, key=lambda x: monthly_average_prices[x]["average_price"])
best_month_avg_price = monthly_average_prices[best_month]["average_price"]

return f"The best time to book a flight to {destination} is in {best_month} with an average price of ${best_month_avg_price:.2f}."