def getHitmask(image):
    """returns a hitmask using an image's alpha."""
    mask = []
    for x in range(image.get_width()):
        mask.append([])
        for y in range(image.get_height()):
            mask[x].append(bool(image.get_at((x,y))[3])) # get the rgba value if a -- e.g.(255,255,255,255) alpha is 0 which means the object does not exist at that point. => png feature
            # we change that alpha value to boolean value, therefore, when alpha  0 => false  1~255 =>true
    return mask
    # after iteration musk is a 2-D matix of True and False