auto close feature would be helpful

[fasmatikos]

It would be fvery helpful if automatically switch to single layout when we close the file in the next group (or maybe if the group is empty).

[arpit1997]

@mikefowler
Hey some code improvement suggestion for this repo:

• I saw that repo does not have a src folder which is like a standard for every repository on Github
• The code does not follow a code style like PEP8 or PEP257
• One more thing that should be modified is removing the comments, instead using docstring so that it would be more readable and precise.
  😸 😸