Change of serialized value.

        Nonify this value as well.

        :param str value: serialized value to use.

def svalue(self, value):
        """Change of serialized value.

        Nonify this value as well.

        :param str value: serialized value to use.
        """

        if value is not None:  # if value is not None
            self._value = None
            self._error = None

        self._svalue = value