@@can.getOwnKeys()

Return all string keys on an object, including those whose corresponding properties are defined not to be enumerable.

var shapeless = {};

// Nothing enumerable in a shapeless object
shapeless[canSymbol.for('can.getOwnKeys')] = function() { return []; }

var thingsInMyEar = {};
Object.setPrototypeOf(thingsInMyEar, {
    "banana": {
        peeled: false
    }
});

thingsInMyEar[canSymbol('can.getOwnEnumerableKeys')] = function() { 
    return Object.getOwnPropertyNames(this)
        .concat(["banana"]);  // There's always a banana in my ear
};