[his attention is immediately drawn toward the knock, expression brightening when a familiar voice follows the noise.]

Byleth, hello! [the book gets gently set aside, sizhui clambers upright and hurries to meet the other man halfway, a grin having overtaken his face at the realization his friend has made it alright.] Ah... [he trails off momentarily, one hand outstretched in an offer to relieve byleth of his basket if he likes. (perhaps sizhui's also curious about what's in there, but manners first!)

after it dawns on him that he hasn't answered yet, he softly clears his throat and,] Thank you. It's still missing a few things here and there, but I'm hoping to regain items to fill the space soon enough.