'This method is scheduled to be called repeatedly by the pyglet
clock.
Parameters
dt : float
The change in time since the last call.'

def update(self, dt):

    self.model.process_queue()
    sector = sectorize(self.position)
    if (sector != self.sector):
        self.model.change_sectors(self.sector, sector)
        if (self.sector is None):
            self.model.process_entire_queue()
        self.sector = sector
    m = 8
    dt = min(dt, 0.2)
    for _ in xrange(m):
        self._update((dt / m))
