Dict Unpacking in Python

I found dictionary unpacking to be quite useful, when you don't want to mutate things. Code like:

    new_dict = {**old_dict, **update_keys_and_values_dict}

Or even complexer:

    new_dict = {
        **old_dict,
        **{
            key: val
            for key, val in update_keys_and_values_dict
            if key not in some_other_dict
        }
    }

It is quite flexible.

I love the union syntax in 3.9+:

  new_dict = old_dict | update_keys_and_values_dict