Is there a way of calculating the of abstract sums in Cadabra? E.g., is it possible to show that
[a_i, sum_{j} a_j^\dagger a_j] = a_i, where [a_i, a_j^dagger] = delta_{ij}?
I found a similar post here: Sympy: How to get simplified commutators using the second quantization module?, but I couldn’t figure out how to do this for abstract sums...
If this is not possible with cadabra, can I do this with some other software?