quickstart does not work

[hirom-tytlabs]

Hello. Thank you for your interesting work!
I tried quickstart.ipynb, but the following error occurred.
I haven't changed the code, and followed your README.
I also tried 'test.py', but I got the same error.
How do I avoid it?

RemoteTraceback                           Traceback (most recent call last)
RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/home/*****/anaconda3/envs/eph/lib/python3.11/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
                    ^^^^^^^^^^^^^^^^^^^
  File "/home/*****/MAPF/eph-mapf/test.py", line 152, in test_instance
    su, st, nc, ar, ag_pos_ = test_one_case(
                              ^^^^^^^^^^^^^^
  File "/home/*****/MAPF/eph-mapf/src/utils/utils.py", line 21, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/*****/MAPF/eph-mapf/test.py", line 111, in test_one_case
    (obs, last_act, pos), _, done, info = env.step(actions)
                                          ^^^^^^^^^^^^^^^^^
  File "/home/*****/MAPF/eph-mapf/src/environment.py", line 367, in step
    if target_agent_id:
ValueError: The truth value of an empty array is ambiguous. Use `array.size > 0` to check that an array is not empty.
"""

The above exception was the direct cause of the following exception:

ValueError                                Traceback (most recent call last)
Cell In[5], line 1
----> 1 results = test_model('65000', config=config)

File ~/MAPF/eph-mapf/test.py:285, in test_model(checkpoint_name, config)
    271 ret = tqdm(pool.imap(test_instance, tests), total=len(tests))
    273 if config.ensemble is not None:
    274     (
    275         success,
    276         steps,
    277         num_comm,
    278         arrived,
    279         all_successes,
    280         all_steps,
    281         all_num_comms,
    282         all_arrived,
    283         best_pos,
    284         all_pos,
--> 285     ) = zip(*ret)
    286 else:
    287     success, steps, num_comm, arrived, best_pos = zip(*ret)

File ~/anaconda3/envs/eph/lib/python3.11/site-packages/tqdm/std.py:1181, in tqdm.__iter__(self)
   1178 time = self._time
   1180 try:
-> 1181     for obj in iterable:
   1182         yield obj
   1183         # Update and possibly print the progressbar.
   1184         # Note: does not call self.update(1) for speed optimisation.

File ~/anaconda3/envs/eph/lib/python3.11/multiprocessing/pool.py:873, in IMapIterator.next(self, timeout)
    871 if success:
    872     return value
--> 873 raise value

ValueError: The truth value of an empty array is ambiguous. Use `array.size > 0` to check that an array is not empty.