'Returns whether this bounding box overlaps with the other bounding box,
not including the edges.'

def fully_overlaps(self, other):

    (ax1, ay1, ax2, ay2) = self.extents
    (bx1, by1, bx2, by2) = other.extents
    if (ax2 < ax1):
        (ax2, ax1) = (ax1, ax2)
    if (ay2 < ay1):
        (ay2, ay1) = (ay1, ay2)
    if (bx2 < bx1):
        (bx2, bx1) = (bx1, bx2)
    if (by2 < by1):
        (by2, by1) = (by1, by2)
    return ((ax1 < bx2) and (bx1 < ax2) and (ay1 < by2) and (by1 < ay2))
