<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _dequeue_update(self,change):

 """ Only update when all changes are done """

        self._update_count -=1
        if self._update_count !=0:
            return
        self.update_shape(change)