def assert_concrete_activerecord_class(class_name)
      if class_name.constantize.abstract_class?
        raise format(::PaperTrail::ModelConfig::E_HPT_ABSTRACT_CLASS, @model_class, class_name)
      end
    end
def assert_concrete_activerecord_class(class_name)
      if class_name.constantize.abstract_class?
        raise format(::PaperTrail::ModelConfig::E_HPT_ABSTRACT_CLASS, @model_class, class_name)
      end
    end
Raises an error if the provided class is an `abstract_class`.
 @api private