Python 2.6.3 (r263:75183, Oct  2 2009, 11:22:08)
>>> import IN
>>> help(IN)

-- contain following lines:
"MODULE DOCS
    http://docs.python.org/library/IN"
, but server returns 404 error:
"The requested URL /library/IN was not found on this server."
and no docs found in source distribution:
$ cat ~/terrarium/sources/py26st/Doc/library/IN.rst
cat: /home/roma/terrarium/sources/py26st/Doc/library/IN.rst: No such 
file or directory