IndexError: index 10 is out of bounds for axis 0 with size 10

i am trying to run a Github repo for voltage control of various distribution system like IEEE10 bus, 23 bus and 30 bus system. When main files calls file for power flow calculations it calls another file ext2int to convert external numbering to internal, which generates error as given below,
‘bs[n2i[ppc[“branch”][:, T_BUS].astype(int)]] ).astype(bool)’. I have created issues to this repo on github as well, but did not find any response. project line is given below. Plz help me out to resolve this issue,.
Link: GitHub - sogno-platform/covee: Coordinated Voltage Control