Update and/or return the CPU using the psutil library.

def __get_cpu(self):
        """Update and/or return the CPU using the psutil library."""
        # Never update more than 1 time per cached_time
        if self.timer_cpu.finished():
            self.cpu_percent = psutil.cpu_percent(interval=0.0)
            # Reset timer for cache
            self.timer_cpu = Timer(self.cached_time)
        return self.cpu_percent