Just a note: as of this week (GH-31888), we no longer use bytes objects to store bytecode. Instead, the instructions are stored as part of the PyCodeObject struct.

(Of course, we still use bytes objects for the various exception handling and debugging tables attached to code objects, but these are very cold fields by comparison.)

Not to say this work isn't worthwhile, but it probably isn't worth doing for `co_code` *alone*.