why is error squiggle lines of pylint not showing in python visual studio code?

i'm using vscode version 1.41.1 for coding in python 3 in Ubuntu version 18.04. but suddenly I noticed error-squiggle-lines are not working for python(it works for other languages). and i am using Microsoft's Python extension. I don't know why this happened (Maybe after i was trying shortcuts in vs code). this is what i have tried

• I thought maybe it's because i installed anaconda so uninstalled it but that didn't fix it.
• then I re-installed vs code after deleting its config from .config/code but that didn't work either.
• also also set the python linting to true from command palette

I want it to show error squiggle lines again like in this one but it's not showing error squiggle lines:

how to get the squiggle lines to work again?