Hi,

I am currently practicing Cadabra 2 and would like to ask a simple (and maybe stupid) question. I wrote down the following code:

```
{t,x,y,z}::Coordinate;
{\mu,\nu,\rho,\sigma}::Indices(values={t,x,y,z},vectors);
\partial{#}::PartialDerivative;
f::Depends(t,x,y,z,\partial);
ex:= \partial_{\mu}{1+f};
```

Then I want to evaluate ex to get \partial*{\mu}{f}. How can I do that? I tried some commands but nothing did work well.
Or, is there any idea to automatically get 0 when we write down \partial*{\mi}{some constant} in the definition or when \partial_{\mu}{const} is evaluated on the way of calculations?