code: def topsWS(symbols=None, on_data=None):
      '''https://iextrading.com/developer/docs/#tops'''
      symbols = _strToList(symbols)
      if symbols:
          sendinit = ('subscribe', ','.join(symbols))
          return _stream(_wsURL('tops'), sendinit, on_data)
      return _stream(_wsURL('tops'), on_data=on_dataf topsWS(symbols=None, on_data=None):
      '''https://iextrading.com/developer/docs/#tops'''
      symbols = _strToList(symbols)
      if symbols:
          sendinit = ('subscribe', ','.join(symbols))
          return _stream(_wsURL('tops'), sendinit, on_data)
      return _stream(_wsURL('tops'), on_data=on_data)
docs: https://iextrading.com/developer/docs/#tops