This methods load the IWNLP.Lemmatizer json file and creates a dictionary
         of lowercased forms which maps each form to its possible lemmas.

def load(self, lemmatizer_path):
        """
        This methods load the IWNLP.Lemmatizer json file and creates a dictionary
         of lowercased forms which maps each form to its possible lemmas.
        """
        self.lemmatizer = {}
        with io.open(lemmatizer_path, encoding='utf-8') as data_file:
            raw = json.load(data_file)
            for entry in raw:
                self.lemmatizer[entry["Form"]] = entry["Lemmas"]
        self.apply_blacklist()