chore: update python examples

Author: mwfarb

content/python/attributes/submodel_parent.md

@@ -0,0 +1,42 @@
+---
+title: SubmodelParent
+layout: default
+parent: Attributes
+grand_parent: Python Library
+---
+
+# Sub-Model Parent
+
+When this object is parented to a hierarchical model, it attaches to a named sub-component of that model instead of the root position. Requires `parent` attribute.
+
+This program loads a URDF model of a robot arm, and then attaches a see-though green ball at the tip of the armature at the sub-model component named `joint_6_t-flange` of the URDF model.
+
+Additional Python properties are available in the [SubmodelParent API Reference](/content/python-api/attributes/submodel_parent).
+
+```python
+from arena import *
+
+scene = Scene(host="arenaxr.org", scene="example")
+
+@scene.run_once
+def make_model_container():
+robot_arm = UrdfModel(
+    object_id="robot_arm",
+    position=(0, 0, -3),
+    rotation=(-90, 0, 0),
+    scale=(1, 1, 1),
+    url="/store/users/mwfarb/xacro/motoman_gp4_support/urdf/gp4.xacro",
+    urlBase="/store/users/mwfarb/xacro/motoman_gp4_support",
+)
+scene.add_object(robot_arm)
+green_ball = Sphere(
+    object_id="green_ball",
+    parent=robot_arm.object_id,
+    scale=(0.05, 0.05, 0.05),
+    material={"color": "#00ff00", "transparent": True, "opacity": 0.45},
+    submodel_parent="joint_6_t-flange",
+)
+scene.add_object(green_ball)
+
+scene.run_tasks()
+```

content/python/simple/device-scene.md

@@ -11,13 +11,15 @@ Demonstrate starting two connections, for a scene and a device, and communicatin
 
 ```python
 import json
-import random
 from datetime import datetime
 
 from arena import Box, Device, Material, Scene
 
-box = Box(object_id="box", position=(0, 2, -1), rotation=(0, 0, 0),
-          scale=(2, 2, 2), material=Material(transparent=True, opacity=1))
+box = Box(
+    object_id="box",
+    position=(0, 2, -1),
+    material=Material(transparent=True, opacity=1),
+)
 
 scene = Scene(host="arenaxr.org", scene="example")
 device = Device(host="arenaxr.org", device="robot1")
@@ -34,10 +36,7 @@ def on_recv_message_device(client, userdata, msg):
         box.data.rotation.x += 0.1
         box.data.scale.y -= 0.01
         box.data.material.opacity = (box.data.material.opacity - 0.01) % 1
-        print(scene.update_object(
-            box,
-            click_listener=True,
-        ))
+        print(scene.update_object(box, click_listener=True))
     except:
         pass
 
@@ -46,7 +45,7 @@ device.message_callback_add(CUSTOM_TOPIC, on_recv_message_device)
 @device.run_forever(interval_ms=1000)
 def on_second_publ_message():
     payload = {}
-    d = datetime.now().isoformat()[:-3]+"Z"
+    d = datetime.now().isoformat()[:-3] + "Z"
     payload["timestamp"] = d
     payload = json.dumps(payload)
     device.publish(CUSTOM_TOPIC, payload)