https://bugzilla.wikimedia.org/show_bug.cgi?id=62094
--- Comment #1 from Kunal Mehta (Legoktm) legoktm.wikipedia@gmail.com --- The reason for this is because Site objects are not pickle-able.
import pywikibot, pickle s=pywikibot.Site() f=pickle.dumps(s)
Traceback (most recent call last): [same traceback here] File "/home/km/python/lib64/python2.7/copy_reg.py", line 70, in _reduce_ex raise TypeError, "can't pickle %s objects" % base.__name__ TypeError: can't pickle lock objects