Format of csv files to import (using arangoimp) to greated undirected edges. I used "_to" and "_from" to import directed edges (example: timestamp date ID _to _from 1462750810 7/3/16 311 Media Passengers 1457010729 1/3/17 343 Media Passengers 1480483304 3/16/16 502 Media Passengers ) This created a graph that could be viewed from the Web Interface. But I can't query using INBOUND edges. So I want to convert my graph to an undirected graph to overcome this problem. Im unable to figure out the right CSV format for the same. It throws "missing '_from' or '_to' attribute, offending document:" error everytime I change the format