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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 _delete_vdev_info(self, vdev):
 """handle udev rules file."""

        vdev = vdev.lower()
        rules_file_name = '/etc/udev/rules.d/51-qeth-0.0.%s.rules' % vdev
        cmd = 'rm -f %s\n' % rules_file_name

        address = '0.0.%s' % str(vdev).zfill(4)
        udev_file_name = '/etc/udev/rules.d/70-persistent-net.rules'
        cmd += "sed -i '/%s/d' %s\n" % (address, udev_file_name)
        cmd += "sed -i '/%s/d' %s\n" % (address,
                                        '/boot/zipl/active_devices.txt')
        return cmd