No module named 'libsalt'

[TrinhTuanHung2021]

Hello
Thank you very much for sharing your materials
I had errors when running your models in multi-agents

Traceback (most recent call last):
File "run.py", line 11, in
from test import ddqn_test, sappo_test, ft_simulate, ppornd_test
File "/home/osboxes/Desktop/traffic-signal-optimization/atsc-rl/multi-agent/test.py", line 15, in
from env.salt_PennStateAction import SALT_doan_multi_PSA_test, getScenarioRelatedFilePath, getScenarioRelatedBeginEndTime
File "/home/osboxes/Desktop/traffic-signal-optimization/atsc-rl/multi-agent/env/salt_PennStateAction.py", line 21, in
import libsalt
ModuleNotFoundError: No module named 'libsalt'

I tried to install this module, but I can not install it with pip. Do you have any papers related to your models here?