redefining global symbol: pi

edit

i created a launch file where my robot should open on the gazebo world and when in try to run the launch file using roslaunch i get the following error

redefining global symbol: pi
when processing file: /home/akash/project/src/techman_robot_ros-master/tm_grasp_description/urdf/tm700.urdf.xacro
included from: /home/akash/project/src/techman_robot_ros-master/tm_grasp_description/urdf/tm700_robot.urdf.xacro
xacro.py is deprecated; please use xacro instead
started roslaunch server http://akash:37109/

still i can see my gazebo world but cannot see the robot imported.

and this was the launch file

<launch>
  <arg name="eih" default="false" />
  <arg name="limited" default="false"/>

  <group unless="$(arg eih)">
    <param unless="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot.urdf.xacro'" />
        <param if="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_joint_limited.urdf.xacro'" />
      </group>
      <group if="$(arg eih)">
    <param unless="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_eih.urdf.xacro'" />
    <param if="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_joint_limited_eih.urdf.xacro'" />
  </group>

    <include file="$(find gazebo_ros)/launch/empty_world.launch">
            <arg name="paused" value="false"/>
            <arg name="use_sim_time" value="true"/>
        <arg name="gui" value="true"/>
        <arg name="headless" value="false"/>
        <arg name="debug" value="false"/>
                <arg name="world_name" 
                     value="$(find tm700_moveit_config)/launch/gg.world"/>


    </include>

</launch>