code: def json_document_to_estner_document(jsondoc):
      
      sentences = []
      for json_sent in jsondoc.split_by_sentences():
          snt = Sentence()
          zipped = list(zip(
              json_sent.word_texts,
              json_sent.lemmas,
              json_sent.root_tokens,
              json_sent.forms,
              json_sent.endings,
              json_sent.postags))
          json_toks = [{TEXT: text, LEMMA: lemma, ROOT_TOKENS: root_tokens, FORM: form, ENDING: ending, POSTAG: postag}
                       for text, lemma, root_tokens, form, ending, postag in zipped]
          # add labels, if they are present
          for tok, word in zip(json_toks, json_sent.words):
              if LABEL in word:
                  tok[LABEL] = word[LABEL]
          for json_tok in json_toks:
              token = json_token_to_estner_token(json_tok)
              snt.append(token)
          if snt:
              for i in range(1, len(snt)):
                  snt[i - 1].next = snt[i]
                  snt[i].prew = snt[i - 1]
              sentences.append(snt)
      return Document(sentences=sentences)
docs: Convert an estnltk document to an estner document.
  
      Parameters
      ----------
      jsondoc: dict
          Estnltk JSON-style document.
  
      Returns
      -------
      estnltk.estner.ner.Document
          A ner document.