A few additional words about the pickle module:

• it’s a Python implementation of the serialization process, so the pickled data cannot be exchanged with programs written in other languages like Java or C++. In such cases, you should think about the JSON or XML formats, which could be less convenient than pickling, but when assimilated are more powerful than pickling;
• the pickle module is constantly evolving, so the binary format may differ between different versions of Python. Pay attention that both serializing and deserializing parties are making use of the same pickle versions;
• the pickle module is not secured against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source.