Related to our general investigations into the api docs (#18147), there is the problem that those attributes that are decorated with @cache_readonly no longer have a docstring. Eg:

In [1]: pd.Index.is_unique? Type: NoneType String form: None Docstring: <no docstring> 

If I simply comment out the cache_readonly for this attribute (just as a check this is the culprit), I get:

In [1]: pd.Index.is_unique? Signature: pd.Index.is_unique(self) Docstring: return if the index has unique values File: ~/scipy/pandas/pandas/core/indexes/base.py Type: function 

(although it seems to think it is a function, although inspect.isfunction correctly gives false)

Just posting this here as a reminder to further investigate, and to see if somebody directly has an idea how to fix this (@jreback ?). The main problem is that this decorator is implemented in cython, and we probably can't use something like functools.wraps.