code: private void addAcceptPostHeader() {
          final String rdfTypes = TURTLE + "," + N3 + "," + N3_ALT2 + "," + RDF_XML + "," + NTRIPLES + "," + JSON_LD;
          servletResponse.addHeader("Accept-Post", rdfTypes);
      }
docs: Add the standard Accept-Post header, for reuse.