[DaltonST]

Now nothing is updated, or perhaps a null was updated. mi.set_user_metadata('#genre', custcol) at least updates the unicode literal, as undesirable as that may be. This is the exact code as of this moment:

for book, genre in book_new_genre_final.items(): #dictionary utf-8
mi = Metadata(_('Unknown'))
u_book = book #still in utf8
u_genre = genre #still in utf8
n_book = int(u_book)
if u_book > 0 and u_genre > ' ':
custcol = custom_columns['#genre']
custcol['#value#'] = u_genre
mi.set('#genre', [u_genre])
# mi.set_user_metadata('#genre', custcol)
books_updated.append(n_book)
id_map[n_book] = mi
payload = books_updated
edit_metadata_action = self.gui.iactions['Edit Metadata']
edit_metadata_action.apply_metadata_changes(id_map , callback=self._finish_displaying_results(payload))
else:
xxxxxxxx