code: function appendGraph (toGraph, fromGraph, docURI) {
    fromGraph.statementsMatching(ALL_STATEMENTS)
      .forEach((st) => {
        toGraph.add(st.subject, st.predicate, st.object, st.why)
      })
  }
docs: Appends RDF statements from one graph object to another
  @method appendGraph
  
  @param toGraph {Graph} Graph object to append to
  @param fromGraph {Graph} Graph object to append from
  @param docURI {string} Document URI to use as source