old_contents: """Find top stocks and post them to Twitter."""
  import sys
  import tweetPoster
  import stockPrices
  from stockList import getStockList
  import time
  
  def main():
      # Get the list of stock symobls
      currentStockList = getStockList()
  
      # Get the stock prices
      oldStockPrices = stockPrices.getStockPrices(currentStockList)
  
      # Wait a while for the stock prices to change
      print("Sleeping...")
      time.sleep(30)
      print("Done sleeping.")
  
      # Get the new stock prices
      currentStockPrices = stockPrices.getStockPrices(currentStockList)
  
      # Find the fastest-changing stocks
      topStockPrices = stockPrices.getFastestChangingPrices(currentStockPrices, oldStockPrices)
  
      # Format the tweet text
      tweetText = ""
      for stockPrice in topStockPrices:
          symbol  = stockPrice[0]
          percentage = round(float(stockPrice[1]), 2)
          if percentage > 0:
              percentage = '+' + str(percentage)
          tweetText = tweetText + '#' + symbol + " : " + percentage + '%, '
  
      # Post a tweet of the top stocks
      print tweetText
      tweetPoster.postTweet(tweetText)
  
  if __name__ == '__main__':
      sys.exit(main())
  
new_contents: """Find top stocks and post them to Twitter."""
  import sys
  import tweetPoster
  import stockPrices
  from stockList import getStockList
  import time
  
  def main():
      # Get the list of stock symobls
      currentStockList = getStockList()
  
      # Get the stock prices
      oldStockPrices = stockPrices.getStockPrices(currentStockList)
  
      # Wait a while for the stock prices to change
      print("Sleeping...")
      time.sleep(30)
      print("Done sleeping.")
  
      # Get the new stock prices
      currentStockPrices = stockPrices.getStockPrices(currentStockList)
  
      # Find the fastest-changing stocks
      topStockPrices = stockPrices.getFastestChangingPrices(currentStockPrices, oldStockPrices)
  
      # Format the tweet text
      tweetText = ""
      for stockPrice in topStockPrices:
          symbol  = stockPrice[0]
          percentage = round(float(stockPrice[1]), 2)
          if percentage > 0:
              percentage = '+' + str(percentage)
          else:
              percentage = str(percentage)
          tweetText = tweetText + '#' + symbol + " : " + percentage + '%, '
  
      # Post a tweet of the top stocks
      print tweetText
      tweetPoster.postTweet(tweetText)
  
  if __name__ == '__main__':
      sys.exit(main())
  
subject: Make sure "percentage" is a string before concatenating it.