def ohlc(self, pair, timeframe=None, **kwargs):
        """
        Subscribe to the passed pair's OHLC data channel.
        :param pair: str, Pair to request data for.
        :param timeframe: str, {1m, 5m, 15m, 30m, 1h, 3h, 6h, 12h,
                                1D, 7D, 14D, 1M}
        :param kwargs:
        :return:
        """
        valid_tfs = ['1m', '5m', '15m', '30m', '1h', '3h', '6h', '12h', '1D',
                     '7D', '14D', '1M']
        if timeframe:
            if timeframe not in valid_tfs:
                raise ValueError("timeframe must be any of %s" % valid_tfs)
        else:
            timeframe = '1m'
        pair = 't' + pair if not pair.startswith('t') else pair
        key = 'trade:' + timeframe + ':' + pair
        self._subscribe('candles', key=key, **kwargs)
Subscribe to the passed pair's OHLC data channel.
        :param pair: str, Pair to request data for.
        :param timeframe: str, {1m, 5m, 15m, 30m, 1h, 3h, 6h, 12h,
                                1D, 7D, 14D, 1M}
        :param kwargs:
        :return: