Too bad necessary cooking blands the colours.  Resist the desire to present them in their colourful form.  They contain lectin and
cooking them properly is extremely important:

Raw beans should never be eaten.  Boil for a minimum of ten minutes. Even green beans, such as French or runner beans, contain a small amount of lectins and should not be eaten raw.  Do not cook in a slow cooker as the temperatures will not get high enough and can become even more toxic than in the raw form.
More info – read Curse of the lectins.

I pre-cooked them along with dried chick peas which I had presoaked (however I could have soaked them much longer)  and threw them both in the stuffing for my baked tomatoes/zucchini.

Little known fact:  The plant is a perennial with tuberous roots.  It is usually treated as an annual.

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