def is_valid_ohlc(ohlc_row):
    """ ohlc format: (open,high,low,close,volume) """
    _open, _high, _low, _close, _volume = ohlc_row
    isin_bunds = lambda v: v >= _low and v <= _high
    return _high >= _low and isin_bunds(_open) and isin_bunds(_close) and _volume >= 0