def reattach(self, node, parent, deprel):
        """
        Changes the incoming dependency relation to a node. Makes sure that the
        same change is done in the basic tree and in the enhanced graph.
        """
        if node.deps:
            # If the enhanced graph contains the current basic relation, remove it.
            # Note that the enhanced deprel may contain subtypes that are not in the basic deprel.
            orig_n_deps = len(node.deps)
            node.deps = [x for x in node.deps if x['parent'] != node.parent or re.sub(r':.*', '', x['deprel']) != node.udeprel]
            # Add the new basic relation to the enhanced graph only if the original one was there.
            if len(node.deps) < orig_n_deps:
                node.deps.append({'parent': parent, 'deprel': deprel})
        node.parent = parent
        node.deprel = deprel