raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by relation #{rel.relation.id}.") unless rel.nil?
self.changeset_id = new_node.changeset_id
raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by relation #{rel.relation.id}.") unless rel.nil?
self.changeset_id = new_node.changeset_id