docs: def wordify(self):
          """
          Constructs string of all documents.
  
              :return: document representation of the dataset, one line per document
              :rtype: str
          """
          string_documents = []
          for klass, document in zip(self.resulting_classes, self.resulting_documents):
              string_documents.append("!" + str(klass) + " " + '' .join(document))
          return '\n'.join(string_documents)