Reading and writing Python pickle files, or at least a best effort to do that.
Python's pickle protocol consists out of opcodes and optionally parameters that guide the system through loading a file. The machine has a stack and a dictionary to process data. The protocol has not really a fixed prefix as file, but it normally starts with 0x80 as first opcode to set the protocol version, and then 0x05 or 0x04, the most common protocol numbers. The last opcode is normally a 0x2e, or a dot, that stops the parser from reading.
For parsing, the protocol has only some influence with regarding to loading the correct modules.