The classic super Lie algebras are of type A: $\operatorname{sl}(m+1 \mid n+1)$, $m\neq n$, $\operatorname{psl}(n+1 \mid n+1)$, type B: $\operatorname{osp}(2m+1 \mid 2n)$, type C: $\operatorname{osp}(2 \mid 2n)$, type D: $\operatorname{osp}(2m \mid 2n)$.
But I find some paper they study $\operatorname{psu}(2, 2\mid 4)$. What type is this super Lie algebra? Thank you very much.