make three test cases for this code $($define $($value$-$of$-$ds expr env$)$

$($cond

$(($number$?$ expr$)$ expr$)$

$(($eq$?$ expr 'empty$)\text{'}())$

$(($eq$?($car expr$)\text{'}$if$-$null$)$

$($let $(($condition $($value$-$of$-$ds $($cadr expr$)$ env$)))$

$($if $($null$?$ condition$)$

$($value$-$of$-$ds $($caddr expr$)$ env$)$

$($value$-$of$-$ds $($cadddr expr$)$ env$))))$

$(($eq$?($car expr$)$ 'cons$)$

$($cons $($value$-$of$-$ds $($cadr expr$)$ env$)$

$($value$-$of$-$ds $($caddr expr$)$ env$)))))$