$ python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from lxml import etree
>>> from pickle import dumps
>>> from multiprocessing import Pipe
>>> n = etree.Element('new')
>>> dumps(n)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/pickle.py", line 1366, in dumps
    Pickler(file, protocol).dump(obj)
  File "/usr/lib/python2.6/pickle.py", line 224, in dump
    self.save(obj)
  File "/usr/lib/python2.6/pickle.py", line 306, in save
    rv = reduce(self.proto)
  File "/usr/lib/python2.6/copy_reg.py", line 70, in _reduce_ex
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle _Element objects
>>> p1, p2 = Pipe()
>>> p1.send(n)
>>> p2.recv()
Segmentation fault