>>> from multiprocessing import Process
>>> def a():
...     while 1:
...             pass
...
>>> processing = Process(target=a)
>>> processing.start()
>>> Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Python27\lib\multiprocessing\forking.py", line 381, in main
    self = load(from_parent)
  File "C:\Python27\lib\pickle.py", line 1384, in load
    return Unpickler(file).load()
  File "C:\Python27\lib\pickle.py", line 864, in load
    dispatch[key](self)
  File "C:\Python27\lib\pickle.py", line 1096, in load_global
    klass = self.find_class(module, name)
  File "C:\Python27\lib\pickle.py", line 1132, in find_class
    klass = getattr(mod, name)
AttributeError: 'module' object has no attribute 'a'