$5\mathrm{.}2\mathrm{.}7$ has$\_$won$($board: Board$)$

$->$

$->$ bool

Returns True if the game is won, False otherwise. The game is won if the goal has been achieved;

that is$,$ every cell is filled and all rows, columns and squares on the board contain exactly one of

each digit from $1$ to $9.$

Example:

has$\_$won$($board$\_$three$)$

False

$>$ update$\_$board

$($

$($

$8$

$,$

$8$

$)$

$,$

$5$

$((8,8),5,$ board$\_$three

$)$

$)$

$>$ board$\_$three

$[[[6,8,5,1,3,2,9,4,7],[7,3,4,5,9,8,2,1,6]],$

$[[2,1,9,7,6,4,8,5,3],[9,2,6,8,7,1,5,3,4]],$

$[[8,5,1,3,4,9,6,7,2],[4,7,3,2,5,6,1,8,9]],$

$[[5,6,8,4,2,7,3,9,1],[3,4,2,9,1,5,7,6,8]],$

$[[1,9,7,6,8,3,4,2,5]]]$

$>$ has$\_$won $($board$\_$three$)$

True