arangosh> col = db.example;
[ArangoCollection 139798691, "example" (type document, status loaded)]
arangosh> col.save({ "Hello" : "World" });
{ 
  "error" : false, 
  "_id" : "example/140126371", 
  "_rev" : "140126371", 
  "_key" : "140126371" 
}
arangosh> col.count();
1
arangosh> col.truncate();
arangosh> col.count();
0