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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 request_sensor_list(self, req, msg):
 """Request the list of sensors. The list of sensors is sent as a sequence of #sensor-list informs. Parameters name : str, optional Name of the sensor to list (the default is to list all sensors). If name starts and ends with '/' it is treated as a regular expression and all sensors whose names contain the regular expression are returned. Informs ------- name : str The name of the sensor being described. description : str Description of the named sensor. units : str Units for the value of the named sensor. type : str Type of the named sensor. params : list of str, optional Additional sensor parameters (type dependent). For integer and float sensors the additional parameters are the minimum and maximum sensor value. For discrete sensors the additional parameters are the allowed values. For all other types no additional parameters are sent. Returns ------- success : {'ok', 'fail'} Whether sending the sensor list succeeded. informs : int Number of #sensor-list inform messages sent. Examples -------- :: ?sensor-list #sensor-list psu.voltage PSU\_voltage. V float 0.0 5.0 #sensor-list cpu.status CPU\_status. \@ discrete on off error !sensor-list ok 5 ?sensor-list cpu.power.on #sensor-list cpu.power.on Whether\_CPU\_hase\_power. \@ boolean !sensor-list ok 1 ?sensor-list /voltage/ #sensor-list psu.voltage PSU\_voltage. V float 0.0 5.0 #sensor-list cpu.voltage CPU\_voltage. V float 0.0 3.0 !sensor-list ok 2 """

        exact, name_filter = construct_name_filter(msg.arguments[0]
                                                   if msg.arguments else None)
        sensors = [(name, sensor) for name, sensor in
                   sorted(self._sensors.iteritems()) if name_filter(name)]

        if exact and not sensors:
            return req.make_reply("fail", "Unknown sensor name.")

        self._send_sensor_value_informs(req, sensors)
        return req.make_reply("ok", str(len(sensors)))