When I run `manage.py makemessages` I found some messages which were in the `.po` file like this:

```
msgid "Example"
msgstr "Example"

```

Transformed to this, after I ran the command:

```
#~ msgid "Example"
#~ msgstr "Example"

```

* What does `#~` means? Since the translation of those messages doesn't work anymore, I suppose it is a comment.
* What can I do to prevent Django commenting out (or "`#~`ing") pre-existing messages in the translation file?