Setter for **self.__text_color** attribute.

        :param value: Attribute value.
        :type value: int or QColor

def text_color(self, value):
        """
        Setter for **self.__text_color** attribute.

        :param value: Attribute value.
        :type value: int or QColor
        """

        if value is not None:
            assert type(value) in (Qt.GlobalColor, QColor), \
                "'{0}' attribute: '{1}' type is not 'int' or 'QColor'!".format("text_color", value)
        self.__text_color = value