Is it possible to get (anti)commutator directly? I have a try, for example

```
{a,b,c,d,e,f,g,h}::NonCommuting.
ex:=a b c d-c d b a+e f g h+g h f e;
substitute(_,$A?? B??-B?? A??->\commutator{A??}{B??},A?? B??+B?? A??->\anticommutator{A??}{B??}$);
```

but it doesn't work.