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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 WaitForVirtualMachineShutdown( self, vm_to_poll, timeout_seconds, sleep_period=5 ):
 """ Guest shutdown requests do not run a task we can wait for. So, we must poll and wait for status to be poweredOff. Returns True if shutdown, False if poll expired. """

        seconds_waited = 0  # wait counter
        while seconds_waited < timeout_seconds:
            # sleep first, since nothing shuts down instantly
            seconds_waited += sleep_period
            time.sleep(sleep_period)

            vm = self.get_vm(vm_to_poll.name)
            if vm.runtime.powerState == \
                    vim.VirtualMachinePowerState.poweredOff:
                return True

        return False