code: def to_dict(self):
          
          if self._dict is not None:
              return self._dict
  
          result = {}
          for key in self.ATTRIBUTES:
              value = getattr(self, key)
              if value:
                  result[key] = value
          self._dict = result
          return result
docs: Get a dictionary of the attributes of this Language object, which
          can be useful for constructing a similar object.