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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def on_vm_process_priority_change(self, priority):
 """Triggered when process priority of the associated virtual machine have changed. in priority of type :class:`VMProcPriority` The priority which set. raises :class:`VBoxErrorInvalidVmState` Session state prevents operation. raises :class:`VBoxErrorInvalidObjectState` Session type prevents operation. raises :class:`VBoxErrorVmError` Error from underlying level. See additional error info. """

        if not isinstance(priority, VMProcPriority):
            raise TypeError("priority can only be an instance of type VMProcPriority")
        self._call("onVMProcessPriorityChange",
                     in_p=[priority])