protected int assertIndexBounds(int index) {
        if (index < 0 || index >= degree()) {
            throw new IndexOutOfBoundsException("index " + index + " is illegal. The degree of this Tuple is " + degree() + ".");
        }
        return index;
    }
Returns if this Tuple can contain null elements.

@return if this Tuple can contain null elements
common-parent/tuple/src/main/java/com/speedment/common/tuple/internal/BasicAbstractTuple.java