$ sudo apt-get remove flake8 

Uninstall flake8 including dependent package

If you would like to remove flake8 and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove flake8 

Use Purging flake8

If you use with purge options to flake8 package all the configuration and dependent packages will be removed.

$ sudo apt-get purge flake8 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove flake8 

See Also,