code: def get_fields(self):
          
          if self.__cache_all_fields is None:
              self.__cache_all_fields = []
              for i in self.get_classes():
                  for j in i.get_fields():
                      self.__cache_all_fields.append(j)
          return self.__cache_all_fields
docs: Return all field objects
  
          :rtype: a list of :class:`EncodedField` objects