arangosh> var graph_module = require("org/arangodb/general-graph");
arangosh> graph_module._undirectedRelation("marriage", ["female", "male"]);
{ 
  "collection" : "marriage", 
  "from" : [ 
    "female", 
    "male" 
  ], 
  "to" : [ 
    "female", 
    "male" 
  ] 
}