Musharna forewarn

[pokemaster1970]

If your opponent only has one card left in his deck, can he use Musharna's ability Forewarn (Once during your turn (before your attack), you may look at the top 2 cards of your deck, choose 1 of them, and put it into your hand. Put the other card back on top of your deck.)?

I think not, because he can't fulfill the obligation of returning a card to the deck after choosing a card, and placing it in his hand.

Thank you

 

[PokePop]

In this case, you would do as much as you can, which is to look at one card and keep one.