052d40ae98
calling `wally_psbt_finalize` doesn't return a status indicator; instead you must call `psbt_is_finalized` to check that it's eligible for 'extraction' -- extraction will fail if the psbt is not in a finalized state.
These are standard bitcoin manipulation routines which should be provided by any normal bitcoin library in whatever language you choose. The ones here are standalone ones taken from bitcoin core and some I wrote, many taken from bitcoin-iterate and pasted in here.