The following works well:

```
from textwrap import fill
print(fill("hello-there", 8)) 

```

Outputs:

```
hello-
there

```

However, I am using a lot of text where words are separated with **underscores, not hyphens**. The option `break_on_hyphens` is great but there seems to be no way to specify other separators.

I looked around and was really surprised to not find anything on this. Does anyone have any idea of the best way to proceed?