Add ability to describe multiple arms using xs_launch (#65)

* [xs_modules] Add ability to describe multiple arms

* Fix arg ordering

* Add missing typing to args

interbotix_xs_toolbox/interbotix_xs_modules/interbotix_xs_modules/xs_launch/xs_launch.py

@@ -47,39 +47,53 @@ class DeclareInterbotixXSArmRobotDescriptionLaunchArgument(DeclareLaunchArgument
     def __init__(
         self,
         *,
-        default_value: Optional[SomeSubstitutionsType] = Command([
-            FindExecutable(name='xacro'), ' ',
-            PathJoinSubstitution([
-                FindPackageShare('interbotix_xsarm_descriptions'),
-                'urdf',
-                LaunchConfiguration('robot_model')
-            ]), '.urdf.xacro ',
-            'robot_name:=', LaunchConfiguration('robot_name'), ' ',
-            'base_link_frame:=', LaunchConfiguration('base_link_frame'), ' ',
-            'use_gripper:=', LaunchConfiguration('use_gripper'), ' ',
-            'show_ar_tag:=', LaunchConfiguration('show_ar_tag'), ' ',
-            'show_gripper_bar:=', LaunchConfiguration('show_gripper_bar'), ' ',
-            'show_gripper_fingers:=', LaunchConfiguration('show_gripper_fingers'), ' ',
-            'use_world_frame:=', LaunchConfiguration('use_world_frame'), ' ',
-            'external_urdf_loc:=', LaunchConfiguration('external_urdf_loc'), ' ',
-            'hardware_type:=', LaunchConfiguration('hardware_type'), ' ',
-        ]),
+        robot_description_launch_config_name: Text = 'robot_description',
+        robot_model_launch_config_name: Text = 'robot_model',
+        robot_name_launch_config_name: Text = 'robot_name',
+        default_value: Optional[SomeSubstitutionsType] = None,
         **kwargs
     ) -> None:
         """
         Construct the modified DeclareLaunchArgument object.
 
+        :param robot_description_launch_config_name: Name of the robot description launch
+            configuration. This is typically only changed when multiple arms are to be launched.
+            Defaults to `robot_description`
+        :param robot_model_launch_config_name: Name of the robot model launch configuration.
+            This is typically only changed when multiple arms are to be launched. Defaults to
+            `robot_model`
+        :param robot_name_launch_config_name: Name of the robot name launch configuration.
+            This is typically only changed when multiple arms are to be launched. Defaults to
+            `robot_name`
         :param default_value: The default model given to the parent DeclareLaunchArgument; if you
             want to override this value, it must follow the convention in this object's source
         """
+        if default_value is None:
+            default_value = Command([
+                FindExecutable(name='xacro'), ' ',
+                PathJoinSubstitution([
+                    FindPackageShare('interbotix_xsarm_descriptions'),
+                    'urdf',
+                    LaunchConfiguration(robot_model_launch_config_name)
+                ]), '.urdf.xacro ',
+                'robot_name:=', LaunchConfiguration(robot_name_launch_config_name), ' ',
+                'base_link_frame:=', LaunchConfiguration('base_link_frame'), ' ',
+                'use_gripper:=', LaunchConfiguration('use_gripper'), ' ',
+                'show_ar_tag:=', LaunchConfiguration('show_ar_tag'), ' ',
+                'show_gripper_bar:=', LaunchConfiguration('show_gripper_bar'), ' ',
+                'show_gripper_fingers:=', LaunchConfiguration('show_gripper_fingers'), ' ',
+                'use_world_frame:=', LaunchConfiguration('use_world_frame'), ' ',
+                'external_urdf_loc:=', LaunchConfiguration('external_urdf_loc'), ' ',
+                'hardware_type:=', LaunchConfiguration('hardware_type'), ' ',
+            ]),
         super().__init__(
-            name='robot_description',
+            name=robot_description_launch_config_name,
             default_value=default_value,
             description=(
                 'URDF of the robot; this is typically generated by the xacro command.'
             ),
             choices=None,
-            **kwargs
+            **kwargs,
         )
 
 
@@ -242,9 +256,12 @@ def declare_interbotix_xsarm_robot_description_launch_arguments(
     use_world_frame: Text = 'true',
     external_urdf_loc: Text = '',
     hardware_type: Text = 'actual',
+    robot_description_launch_config_name: Text = 'robot_description',
+    robot_model_launch_config_name: Text = 'robot_model',
+    robot_name_launch_config_name: Text = 'robot_name',
 ) -> List[DeclareLaunchArgument]:
     """
-    Return the `robot_description` DeclareLaunchArgument and its required children.
+    Return a robot description DeclareLaunchArgument and its required children.
 
     DeclareLaunchArgument objects:
         - `base_link_frame`
@@ -338,7 +355,11 @@ def declare_interbotix_xsarm_robot_description_launch_arguments(
                 'hardware, or hardware simulated in Gazebo.'
             ),
         ),
-        DeclareInterbotixXSArmRobotDescriptionLaunchArgument(),
+        DeclareInterbotixXSArmRobotDescriptionLaunchArgument(
+            robot_description_launch_config_name=robot_description_launch_config_name,
+            robot_model_launch_config_name=robot_model_launch_config_name,
+            robot_name_launch_config_name=robot_name_launch_config_name,
+        ),
     ]