Setter for **self.__indent_width** attribute.

        :param value: Attribute value.
        :type value: int

def indent_width(self, value):
        """
        Setter for **self.__indent_width** attribute.

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

        if value is not None:
            assert type(value) is int, "'{0}' attribute: '{1}' type is not 'int'!".format("indent_width", value)
        self.__indent_width = value