code: def set_value(self, instance, value):
          '''Set the ``value`` for this :class:`Field` in a ``instance``
  of a :class:`StdModel`.'''
          setattr(instance, self.attname, self.to_python(value)f set_value(self, instance, value):
          '''Set the ``value`` for this :class:`Field` in a ``instance``
  of a :class:`StdModel`.'''
          setattr(instance, self.attname, self.to_python(value))
docs: Set the ``value`` for this :class:`Field` in a ``instance``
  of a :class:`StdModel`.