if (c.isInterface()) return null;
    public static Invokeable<?, ?> invokeableFor(Class c) {        Invokeable<?, ?> i= null;        if (null != (i= typeMap.get(c))) return i;    // Direct hit                // Search for classes the specified class is assignable from        for (Class key: typeMap.keySet()) {            if (!key.isAssignableFrom(c)) continue;            // Cache results. Next time around, we'll have a direct hit            i= typeMap.get(key);            typeMap.put(c, i);            return i;        }                // Nothing found, return NULL. This will make representationOf()        // use the default object serialization mechanism (field-based)        return null;    }