Marshalling (or serialization) is the operation when we take an arbitrary data structure and convert it into a string in a way that we can convert the string back to the same data structure.
Marshalling can be used to save data persistent between execution of the same script, to transfer data between processes, or even between machines. In some cases it can be used to communicate between two processes written in different programming languages.
The marshal module provides such features but it is not recommended as it was built for internal object serialization for python.
The pickle module was designed for this task.
The json module can be used too.