# how to re-order factors

I have

```
x,y, dx, dy= var("x, y, dx, dy");
def iD(f): return diff(f, x)*dx + diff(f,y)*dy;
```

`iD(x^3*y^5)`

returns

```
5*dy*x^3*y^4 + 3*dx*x^2*y^5
```

is there a way to have it return the differentials always at the end as in

```
5*x^3*y^4*dy + 3*x^2*y^5*dx
```

thank you