adding NAO humanoid robot as walker in locomotion soccer environment

how to add new walker in locomotion soccer environments ??

used **quickstart** codebase

```
import numpy as np
from dm_control.locomotion import soccer as dm_soccer
env = dm_soccer.load(team_size=2,
time_limit=10.0,
disable_walker_contacts=False,
enable_field_box=True,
terminate_on_goal=False,
walker_type=dm_soccer.WalkerType.BOXHEAD)

action_specs = env.action_spec()
timestep = env.reset()
while not timestep.last():
actions = []
for action_spec in action_specs:
action = np.random.uniform(
action_spec.minimum, action_spec.maximum, size=action_spec.shape)
actions.append(action)
timestep = env.step(actions)
```

we will find that we have 3 types of walker [ ant, boxhead, humanoid ]

**tried to import my custom walker by changing xml paths in walkers src files [ ant.py, boxhead.py, humanoid.py] and display it by explore.py but nothing changes.....**

my custom model is **NAO** robot ,I've been working on robot's xml , by converting urdf file to xml file using compile.exe provided by **MuJoCo Pro version 2.00** , assets directory with dae files and stl files, after compiling robot's xml works well on MuJoCo Pro

**NAO urdf file** from [https://github.com/ros-naoqi/nao_robot/blob/master/nao_description/urdf/naoV50_generated_urdf/nao.urdf](url)