input: Write a function to design a web server in Python using the Flask framework that serves a JSON object containing the current temperature for a city based on the city name given in the request.
  
  assert get_temp_of_city('New York')=={'temperature': 278.15}
  assert get_temp_of_city('London')=={'temperature': 283.15}
  assert get_temp_of_city('Tokyo')=={'temperature': 290.15}
  assert get_temp_of_city('Sydney')=={'temperature': 295.15}
  assert get_temp_of_city('Dubai')=={'temperature': 305.15}
output: def get_temp_of_city(city):
      temp_data = {
          'New York': 278.15,
          'London': 283.15,
          'Tokyo': 290.15,
          'Sydney': 295.15,
          'Dubai': 305.15
      }
      return {'temperature': temp_data.get(city, None)}