docs: def update(self, **kwargs):
          """
          Mass-assign the attributes in +kwargs+ to the object, preventing
          attributes not in __attributes__ from being set.
          """
          for attr, val in kwargs.items():
              if attr in (list(self.__class__.__attributes__) + \
                          list(associations.associations_for(self.__class__))):
                  setattr(self, attr, val)