input: Write a function to get stock quotes using an API request.
  assert get_quote('AAPL') is not None
  assert 'AAPL' in get_quote('AAPL')[0]['symbol']
  assert get_quote('INVALID_TICKER') is None
output: import requests
  
  def get_quote(ticker):
      url = f'https://financialmodelingprep.com/api/v3/quote/{ticker}?apikey=demo'
      response = requests.get(url)
      if response.status_code == 200:
          data = response.json()
          if data:
              return data
      return None