code: def get_instrument_history(self, instrument, candle_format="bidask",
                                 granularity='S5', count=500,
                                 daily_alignment=None, alignment_timezone=None,
                                 weekly_alignment="Monday", start=None,
                                 end=None):
          
          url = "{0}/{1}/candles".format(self.domain, self.API_VERSION)
          params = {
              "accountId": self.account_id,
              "instrument": instrument,
              "candleFormat": candle_format,
              "granularity": granularity,
              "count": count,
              "dailyAlignment": daily_alignment,
              "alignmentTimezone": alignment_timezone,
              "weeklyAlignment": weekly_alignment,
              "start": start,
              "end": end,
          }
          try:
              return self._Client__call(uri=url, params=params, method="get")
          except RequestException:
              return False
          except AssertionError:
              return False
docs: See more:
              http://developer.oanda.com/rest-live/rates/#retrieveInstrumentHistory