isdatadescriptor() was added recently.

nnorwitz · nnorwitz · commit d3d5768e5ecf · 2003-05-29T02:10:31.000Z
diff --git a/Doc/lib/libinspect.tex b/Doc/lib/libinspect.tex
@@ -184,6 +184,7 @@ \subsection{Types and members
   Typically, data descriptors will also have __name__ and __doc__ attributes 
   (properties, getsets, and members have both of these attributes), but this 
   is not guaranteed.
+\versionadded{2.3}
 \end{funcdesc}
 
 \subsection{Retrieving source code
