This library implements Kaitai Struct API for Python.

Kaitai Struct is a declarative language used for describe various binary
data structures, laid out in files or in memory: i.e. binary file
formats, network stream packet formats, etc.

It is similar to Python’s [construct] and [Construct3], but it is
language-agnostic. The format description is done in YAML-based .ksy
format, which then can be compiled into a wide range of target
languages.

WWW: http://kaitai.io/