Using a reduction, show that the language

$AL{L}_{\text{D}\text{F}\text{A}}=\{($:$D$:$)$:$Dis$ a DFA and $L(D)={}^{**}\}$

is decidable $($i$.$e$.$ for a given alphabet $,D$ accepts all strings composed of that alphabet$).$

You may use any problem we have shown to be decidable in lecture for a reduction.