@Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        BasicPredGraph<N, E> other = (BasicPredGraph<N, E>) obj;
        if (internalNode == null) {
            if (other.internalNode != null)
                return false;
        } else if (!internalNode.equals(other.internalNode))
            return false;
        return true;
    }