Extended pickling support for Python 3 objects

 cloudpickle makes it possible to serialize Python constructs not supported
 by the default `pickle` module from the Python standard library.
 .
 cloudpickle is especially useful for cluster computing where Python
 expressions are shipped over the network to execute on remote hosts, possibly
 close to the data.
 .
 Among other things, `cloudpickle` supports pickling for lambda expressions,
 functions and classes defined interactively in the `__main__` module.
 .
 This contains the Python 3 version.