Vi command is throwing error......I wonder why

Respected Sir,
In python for robotics course, I run the command vi and it throws error. It was not coming before. But I was taking my college classes online and when I came back to it, it started throwing this error.

Why suddenly this error and what’s the solution?
Thank you

Hello @abdulbasitisdost,

This means that you have another Shell with a vi session of the same file opened, or that something went wrong when you tried to exit the session. In any case, you have the steps you should follow to solve the issue in the point (2) of the image you shared.