error when lancing the launch file

[houcem1234]

when i lance ublox_device.launch ,it gives me an error arg ublox node to be set.here is my launch file.

<launch>
<arg name="ublox_logger"/>
<arg name="nmea" doc="name of param file, e.g. rover"/>
<arg name="output" default="screen"/>
<arg name="respawn" default="true"/>
<arg name="respawn_delay" default="30"/>
<arg name="clear_params" default="true"/>
<node pkg="ublox_gps" type="ublox_gps" name="$( arg ublox_logger)" output="$(arg output)" clear_params="$(arg clear_params)" respawn="$(arg respawn)" respawn_delay="$(arg respawn_delay)">
<rosparam command="load" file="$(find ublox_gps)/config/$(nmea).yaml"/>
</node>
</launch>