input: Write a function to display the information of three different cities. The function should take the city name, country, latitude, and continent as parameters and print the formatted information. If the parameters passed to the function are not valid or empty, it should return a message stating that the input is invalid.
  assert get_city_info('Edinburgh', 'Scotland', '54.6°N', 'UK')=="City: Edinburgh, Country: Scotland, Latitude: 54.6°N, Continent: UK"
  assert get_city_info('Paris', 'France', '48.86°N', 'Europe')=="City: Paris, Country: France, Latitude: 48.86°N, Continent: Europe"
  assert get_city_info('Dhaka', 'Bangladesh', '23.78°N', 'Asia')=="City: Dhaka, Country: Bangladesh, Latitude: 23.78°N, Continent: Asia"
  assert get_city_info('', '', '', '')=="Invalid input: empty or invalid parameters"
  assert get_city_info(None, None, None, None)=="Invalid input: empty or invalid parameters"
output: def get_city_info(city, country, latitude, continent):
      if not city or not country or not latitude or not continent:
          return "Invalid input: empty or invalid parameters"
      return f"City: {city}, Country: {country}, Latitude: {latitude}, Continent: {continent}"