docs: function indexTriple(g, { subject, predicate, object }) {
    if (!workingPredicates.includes(predicate)) return;
    if (!(isIri(subject) && isIri(predicate)) || g[subject] && g[subject][predicate] && g[subject][predicate].includes(object)) return;
  
    upsert(g, subject, predicate, object);
  
    g.nTriples++;
  
    if (isIri(object)) upsert(g, object, `_${predicate}`, subject);
  }