Unable to get batchspawner working

[debug_log.txt](https://github.com/jupyterhub/batchspawner/files/3377310/debug_log.txt)
[jupyterhub_config.txt](https://github.com/jupyterhub/batchspawner/files/3377311/jupyterhub_config.txt)
[pbs_setup.txt](https://github.com/jupyterhub/batchspawner/files/3377312/pbs_setup.txt)

Trying a set up where we would have JupyterHub configured on host XX.XX.XX.XX and want to use batchspawner to spawn single user notebooks on host YY.YY.YY.YY
But the spawn is failing with below error and hence unable to progress.
jupyterhub_config.py file and the execution log generated by executing jupyterhub with --debug has been uploaded here.

Please guide as it seems I'm doing something fundamentally wrong here!

ERROR:asyncio:Task exception was never retrieved
future: exception=AssertionError()>
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/jupyterhub/handlers/base.py", line 889, in spawn_single_user
timedelta(seconds=self.slow_spawn_timeout), finish_spawn_future
File "/usr/local/lib/python3.6/site-packages/jupyterhub/handlers/base.py", line 807, in finish_user_spawn
await spawn_future
File "/usr/local/lib/python3.6/site-packages/jupyterhub/user.py", line 642, in spawn
raise e
File "/usr/local/lib/python3.6/site-packages/jupyterhub/user.py", line 546, in spawn
url = await gen.with_timeout(timedelta(seconds=spawner.start_timeout), f)
File "/usr/local/lib/python3.6/site-packages/tornado/gen.py", line 748, in run
yielded = self.gen.send(value)
File "/usr/local/lib/python3.6/site-packages/batchspawner/batchspawner.py", line 320, in start
assert self.state_ispending()

Also, there is no clear documentation available to set this up, so if this can kindly be looked at or if someone can kindly share any guide to implement this set-up that will be really helpful.