Python uses an object structure that is available in a pickle. It is the serialization and decomposition and it also called marshaling or flattening.
Serialization means a process by which an object can be converted into a byte stream, which can be stored on a disc or sent across a network.
The reverse process is pickling is known as unpickling, it transforms byte streams (from binary file or bytes-like objects) back into hierarchy objects, that's why it is true.