Setter for **self.__formats** attribute.

        :param value: Attribute value.
        :type value: FormatsTree

def formats(self, value):
        """
        Setter for **self.__formats** attribute.

        :param value: Attribute value.
        :type value: FormatsTree
        """

        if value is not None:
            assert type(value) is FormatsTree, "'{0}' attribute: '{1}' type is not 'FormatsTree'!".format(
                "formats", value)
        self.__formats = value