`ParameterNode.get_descendants` doesn't include `ParameterScale` rates and thresholds

[nikhilwoodruff]

Hi there!

I really enjoy OpenFisca, but I recently encountered an issue.

Here is what I did:

Called ParameterNode.get_descendants in a tree with a parameter scale.

Here is what I expected to happen:

Expected an iterator including rates and thresholds from ParameterScale parameters.

Here is what actually happened:

The iterator didn't include the scale parameters.

Here is data (or links to it) that can help you reproduce this issue:

I've written a MWE here on Google Colab.

Context

I identify more as a:

• Developer (I create tools that use the existing OpenFisca code).

Thanks! Happy to tackle this with a PR if desired. (cc @benjello @sandcha)

[benjello]

PR welcome @nikhilwoodruff !

[nikhilwoodruff]

Thanks @benjello! In progress in https://github.com/openfisca/openfisca-core/pull/1113