code: def json_iterator(hdr, rowlist, lang, add_vtype=False):
      
      # Return the header row
      yield hdr if not add_vtype else ((h, 'type') for h in hdr)
      # Now the data rows
      for row in rowlist:
          if lang and not lang_match_json(row, hdr, lang):
              continue
          yield ((row[c]['value'], jtype(row[c])) if c in row else ('', '')
                 for c in hdr)
docs: Convert a JSON response into a double iterable, by rows and columns
      Optionally add element type, and filter triples by language (on literals)