Setter for **self.__style** attribute.

        :param value: Attribute value.
        :type value: Style

def style(self, value):
        """
        Setter for **self.__style** attribute.

        :param value: Attribute value.
        :type value: Style
        """

        if value is not None:
            assert type(value) is Style, "'{0}' attribute: '{1}' type is not 'Style'!".format("style", value)
            style = Style()
            for item in (self.__default_style, value):
                style.update(item)
            value = style
        self.__style = value