input: Write a function to get the current stock price for a given ticker symbol using the Finnhub API.
  assert isinstance(getStockPrice('AAPL'), float)
  assert isinstance(getStockPrice('MSFT'), float)
  assert isinstance(getStockPrice('GOOG'), float)
output: import requests
  
  def getStockPrice(ticker):
      api_key = 'YOUR_API_KEY'
      url = f'https://finnhub.io/api/v1/quote?symbol={ticker}&token={api_key}'
      response = requests.get(url)
      data = response.json()
      return data['c']