input: Write a python function to get public air quality data for a specified location and spot, and test it.
  assert get_public_mise(loc='서울', station='강남구') is not None
  assert get_public_mise(loc='부산', station='해운대구') is not None
  assert get_public_mise(loc='대구', station='수성구') is not None
output: import requests
  
  def get_public_mise(loc, station):
      url = f"http://api.airvisual.com/v2/city?city={station}&state={loc}&country=South%20Korea&key=YOUR_API_KEY"
      response = requests.get(url)
      if response.status_code == 200:
          data = response.json()
          return data
      else:
          return None