Swap a card from this hand with a random card from another hand $*$ @param idx index of the card in this hand to be swapped $*$ @param other the other hand $*$ @return true if the swap is successful, false otherwise $*/$ public boolean swap$($int idx, Hand other$)\{//$ Check for a valid index and non$-$empty other hand if $($idx $<0||$ idx $>=$ cardsInHand.size$()||$ other.cardsInHand.isEmpty$())\{$ return false; $\}//$ Both hands must agree to swap if $(!$agreeToSwap$()||!$other.agreeToSwap$())\{$ return false; $\}$