def find_first_nonzero(response):
    """
    Parameters
    ----------
        response : iterable
            Every item is a dictionary which must contain at least keys:
            'open','close', 'high', 'low'.

    Returns
    -------
        int
            First index where the entry is not zero. If none found, return -1.
    """
    first_nonzero = -1
    for i, datapoint in enumerate(response):
        if (
            datapoint["open"] != 0
            or datapoint["close"] != 0
            or datapoint["high"] != 0
            or datapoint["low"] != 0
        ):
            first_nonzero = i
            break  # Find first nonzero point
    return first_nonzero