customize-set-value is an interactive autoloaded compiled Lisp function in `cus-edit.el'.

(customize-set-value VARIABLE VALUE &optional COMMENT)

Set VARIABLE to VALUE, and return VALUE. VALUE is a Lisp object.

If VARIABLE has a `variable-interactive' property, that is used as if
it were the arg to `interactive' (which see) to interactively read the value.

If VARIABLE has a `custom-type' property, it must be a widget and the
`:prompt-value' property of that widget will be used for reading the value.

If given a prefix (or a COMMENT argument), also prompt for a comment.