Implement __index__ to avoid TypeError

[larsevj]

Issue
Resolves #46

Approach
This makes the tests in resdata pass, but maybe we should add some tests in cwrap?

[andreas-el]

Issue Resolves #46

Approach This makes the tests in resdata pass, but maybe we should add some tests in cwrap?

Yep, we could for example add something like this to test the __index__():

    def test_dunder_index(self):
        class index_enum(BaseCEnum):
            pass

        index_enum.addEnum("ONE", 1)
        index_enum.addEnum("TWO", 2)
        index_enum.addEnum("THREE", 3)

        value_list = [10, 20, 30, 40]
        value = value_list[index_enum.TWO]
        assert(value == 30)

[andreas-el]

I agree, let's add a test to this fixup.

[andreas-el]

Great, and some nice cleanup too! 🚀