code: def historical_rates(self, date, symbols=None):
          
          try:
              if isinstance(date, datetime.date):
                  # Convert date to ISO 8601 format.
                  date = date.isoformat()
  
              symbols = symbols or self.symbols
              payload = self._create_payload(symbols)
  
              url = BASE_URL + date
  
              response = requests.get(url, params=payload)
  
              response.raise_for_status()
  
              return response.json()
          except requests.exceptions.RequestException as ex:
              raise FixerioException(str(ex))
docs: Get historical rates for any day since `date`.
  
          :param date: a date
          :type date: date or str
          :param symbols: currency symbols to request specific exchange rates.
          :type symbols: list or tuple
          :return: the historical rates for any day since `date`.
          :rtype: dict
          :raises FixerioException: if any error making a request.