Glossary ******** .. glossary:: PyFFI Python File Format Interface. Also see :term:`file`, :term:`interface`, and :mod:`pyffi`. file A byte stream. file format See :term:`interface`. file format interface See :term:`interface`. interface An interface provides a semantic translation of a byte stream to an organized collection of named Python objects, which are typically bundled into a classes. spell A transformation that can be applied to a file. toaster Applies one or more spells to all files of all subdirectories of a given directory.