def compute_edge_phids_from_transactions(transactions, edgetype):
    final_phids = {}
    for trns in transactions:
        try:
            metadata = json.loads(trns[9])
            if "edge:type" in metadata.keys() and metadata[
                    "edge:type"] is edgetype:

                # removed phids:
                phids = json.loads(trns[7])
                for phid in phids:
                    final_phids.setdefault(phid, False)

                # added phids:
                phids = json.loads(trns[8])
                for phid in phids:
                    final_phids.setdefault(phid, True)
        except:
            pass

    return [key for key, val in final_phids.items() if val is True]