text: from datetime import datetime, timedelta
  from data_manager import DataManager
  from flight_search import FlightSearch
  from notification_manager import NotificationManager
  
  ORIGIN_CITY_IATA = "LON"
  
  data_manager = DataManager()
  flight_search = FlightSearch()
  notification_manager = NotificationManager()
  
  sheet_data = data_manager.get_destination_data()
  
  if sheet_data[0]["iataCode"] == "":
      city_names = [row["city"] for row in sheet_data]
      data_manager.city_codes = flight_search.get_destination_codes(city_names)
      data_manager.update_destination_codes()
      sheet_data = data_manager.get_destination_data()
  
  destinations = {
      data["iataCode"]: {
          "id": data["id"],
          "city": data["city"],
          "price": data["lowestPrice"]
      } for data in sheet_data}
  
  tomorrow = datetime.now() + timedelta(days=1)
  six_month_from_today = datetime.now() + timedelta(days=6 * 30)
  
  for destination_code in destinations:
      flight = flight_search.check_flights(
          ORIGIN_CITY_IATA,
          destination_code,
          from_time=tomorrow,
          to_time=six_month_from_today
      )
      print(flight.price)
      if flight is None:
          continue
  
      if flight.price < destinations[destination_code]["price"]:
  
          users = data_manager.get_customer_emails()
          emails = [row["email"] for row in users]
          names = [row["firstName"] for row in users]
  
          message = f"Low price alert! Only £{flight.price} to fly from {flight.origin_city}-{flight.origin_airport} to {flight.destination_city}-{flight.destination_airport}, from {flight.out_date} to {flight.return_date}."
  
          if flight.stop_overs > 0:
              message += f"\nFlight has {flight.stop_overs} stop over, via {flight.via_city}."
  
          link = f"https://www.google.co.uk/flights?hl=en#flt={flight.origin_airport}.{flight.destination_airport}.{flight.out_date}*{flight.destination_airport}.{flight.origin_airport}.{flight.return_date}"
  
          notification_manager.send_emails(emails, message, link)
  
  
  