code: def get_ticker(api_code=None):
      
      
      response = util.call_api('ticker' if api_code is None else 'ticker?api_code=' + api_code)
      json_response = json.loads(response)
      ticker = {}
      for key in json_response:
          json_ccy = json_response[key]
          ccy = Currency(json_ccy['last'],
                         json_ccy['buy'],
                         json_ccy['sell'],
                         json_ccy['symbol'],
                         json_ccy['15m'])
          ticker[key] = ccy
      return ticker
docs: Call the 'ticker' method and return a dictionary
      of :class:`Currency` objects.
      
      :param str api_code: Blockchain.info API code (optional)
      :return: a dictionary in the format of ccy_symbol(str):currency(:class:`Currency`)