We have used parallel processing by having some functions being called by
All children processes will inherit that instance at the moment of forking from the parent process. Any changes made to the instance in the children and in the parent will NOT be seen after the fork.
This is how the processes work in Linux — every process has its own memory, protected from other processes (unless you intentionally shared it). It is not Python-specific.
What you are looking for is called IPC (Inter-Process Communication) in general. There are multiple ways how the processes can communicate with each another. You might want to use pipes or the shared memory.
In Python, read this: https://docs.python.org/2/library/multiprocessing.html#sharing-state-between-processes