Donkercarシュミレーターの環境構築

前提・実現したいこと

DonkeyCarシュミレータで強化学習の実装を試みています．

こちらの記事を参考に環境構築を試みています．強化学習のPythonスクリプトddqn.pyを実行した時に以下のエラーが発生しました．
https://qiita.com/bathtimefish/items/a9b23681720527c0bd7e

発生している問題・エラーメッセージ

python
1$ python ddqn.py --sim=/Applications/donkey_sim.app/Contents/MacOS/donkey_sim
22021-03-25 02:02:33.316657: I tensorflow/core/platform/cpu_feature_guard.cc:142] This TensorFlow binary is optimized with oneAPI Deep Neural Network Library (oneDNN) to use the following CPU instructions in performance-critical operations:  AVX2 FMA
3To enable them in other operations, rebuild TensorFlow with the appropriate compiler flags.
4WARNING:tensorflow:From ddqn.py:203: The name tf.keras.backend.set_session is deprecated. Please use tf.compat.v1.keras.backend.set_session instead.
5
6Traceback (most recent call last):
7  File "/Users/username/opt/miniconda3/lib/python3.8/site-packages/gym/envs/registration.py", line 121, in spec
8    return self.env_specs[id]
9KeyError: 'donkey-warehouse-v0'
10
11During handling of the above exception, another exception occurred:
12
13Traceback (most recent call last):
14  File "ddqn.py", line 361, in <module>
15    run_ddqn(args)
16  File "ddqn.py", line 221, in run_ddqn
17    env = gym.make(args.env_name, conf=conf)
18  File "/Users/username/opt/miniconda3/lib/python3.8/site-packages/gym/envs/registration.py", line 145, in make
19    return registry.make(id, **kwargs)
20  File "/Users/username/opt/miniconda3/lib/python3.8/site-packages/gym/envs/registration.py", line 89, in make
21    spec = self.spec(path)
22  File "/Users/username/opt/miniconda3/lib/python3.8/site-packages/gym/envs/registration.py", line 131, in spec
23    raise error.UnregisteredEnv('No registered env with id: {}'.format(id))
24gym.error.UnregisteredEnv: No registered env with id: donkey-warehouse-v0