def averagePoint(keypointList,indices):
    """Function to find the "centre of mass" for this person.
    It will take the average of the non-zero keypoints
    Args:
        keypointList: 1d array of keypoints.
        indices: a set of indices to average over.
    Returns:
        Average
    """
    tot = 0
    N = 0
    for i in indices:
        if keypointList[i]>0:
            tot += keypointList[i]
            N += 1
    if N > 0:
        return tot / N
    else:
        return 0