code: def remove_stopwords(self, tokens):
          
          if isinstance(tokens, (list, tuple)):
              return [word for word in tokens if word.lower() not in self._stopwords]
          else:
              return ' '.join(
                  [word for word in tokens.split(' ') if word.lower() not in self._stopwords]
              )
docs: Remove all stopwords from a list of word tokens or a string of text.