ttl serialization incorrectly allows spaces in @prefix

[tgbugs]

If a prefix has a space in it there is no warning and we end up with @prefix This has a space: <http://broken.org/oops_> .. This may be an issue with namespace_manager.

[abhishekvickyvyas]

May I contribute to solve this issue.?
In my opinion we need to add warning in function "def bind(self, prefix, namespace, override=True, replace=False):" of "NamespaceManager" class of file \rdflib\namespace.py .

In case if prefix have spaces in it we can show warning and along with it if it is allowed we may replace space with underscore or may do necessary changes as per requirements.
Seeking for positive reply from maintainers and contributors.

[white-gecko]

You are welcome to contribute a pull request solving this issue. But I don't think replacing spaces with underscore is a good solution in this case.

[tgbugs]

Spaces in a prefix should be an error that is detected and raised in NamespaceManger.bind.

[abhishekvickyvyas]

I have submitted my solution of this issue in pull request #1070 . Please check it and let me if any change need to be done in it.

[edmondchuc]

Closing as it seems to be addressed by #1070 already.