I am new in BGA based PCB routing. I am try to use following external python plugin for BGA Fan-routing. but i get the some errors. i have attach the plugin link and upload the error screenshot. kicad-bga-tools
The repository you link to is owned by iysheng, who forked it from Laksen:
Both repositories look like they have not been maintained for the last 4 years.
For Laksen there is even a pull request (made by iysheng) to make a new branch for KiCad V5.
Support for Python V2 ended a year ago (2020-01-01) but due to some missing libraries KiCad still uses python V2 on windows and mac. On Linux, KiCad uses Python V3 but that also has some trouble in for example some of the Footprint Wizards which are now broken. (There is a patch, but it’s held back)