handle_input input hook processor applies the processor
processor on the
hook.hook_before is executed once before the processor and
hook.hook_after is executed once after the processor. By default (without hooks), if an exception
exn has been raised while processing the data it is raised at top-level.
handle_files files hook processor apply a processor on each file of
hook is used once by file. The result is the one given once each file has been processed.