I would much prefer if this was `option_format = '#%s=%r\n' (ie. no space after the `#`).
Perhaps I'm "too python" in my thinking but generally comments that look like this:
```
# This is a comment
```
...is immediately clear that it's something verbose and not meant to be commented in/out. 
However the following looks like something you might want to edit with
```
#value=Foo
```
Also, it means that when you remove the `#` you don't have to worry about formatting. Something that might not matter in some configuration languages like ConfParser. 

Generally, even though verbose text shares the same character as commented out code, they're very different.