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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 generate_host_passthrough(self, vcpu_num):
 """ Generate host-passthrough XML cpu node Args: vcpu_num(str):
 number of virtual CPUs Returns: lxml.etree.Element: CPU XML node """


        cpu = ET.Element('cpu', mode='host-passthrough')
        cpu.append(self.generate_topology(vcpu_num))
        if vcpu_num > 1:
            cpu.append(self.generate_numa(vcpu_num))
        return cpu