Hello, I am trying to declare properties to Cadabra objects inside a python file. Could someone help me with finding the right input syntax, for instance for the property Indices?

Consider the following cadabra notebook contents:

`{ a, b, c, d }::Indices(spacetime, independent=True)`

This assigns the Indices property to the a,b,c,d objects in a cadabra notebook. I would like to do this inside a python notebook. Here is my attempt:

```
import cadabra2 as cad
example_index = ['a', 'b', 'c', 'd']
cad.Indices(example_index_set, space=spacetime, independent=True)
```

This returns the error that example_index is not a Cadabra object, so I'm not understanding the syntax for cad.Indices.

Thanks in advance!