code: def _generate_classes(self, class_types, non_defined, **kwargs):
          
          # kwargs['dataset'] = self
          for class_type in class_types:
              self[class_type[self.smap]] = self._get_rdfclass(class_type,
                                                               **kwargs)\
                                                              (class_type,
                                                               self,
                                                               **kwargs)
  
              self.add_rmap_item(self[class_type[self.smap]],
                                 class_type[self.pmap],
                                 class_type[self.omap])
  
          for class_type in non_defined:
              self[class_type] = RdfClassBase(class_type, self, **kwargs)
              self.add_rmap_item(self[class_type], __a__, None)
          self.__set_classes__
          try:
              self.base_class = self[self.base_uri]
          except KeyError:
              self.base_class = None
docs: creates the class for each class in the data set
  
              args:
                  class_types: list of class_types in the dataset
                  non_defined: list of subjects that have no defined class