def nonZeroMean(arr):
    """Takes the mean of an array not counting None or 0 values."""
    total = 0
    count = 0
    for x in arr:
        if x is not None and x != 0:
            total, count = total + x, count + 1
    count = 1 if count == 0 else count
    return round(total / count, 2)