python - What are all possible pos tags of NLTK?

Question

How do I find a list with all possible pos tags used by the Natural Language Toolkit (nltk)?

Answer 1

The book has a note how to find help on tag sets, e.g.:

nltk.help.upenn_tagset()

Others are probably similar. (Note: Maybe you first have to download tagsets from the download helper's Models section for this)