For example: (cons some-value my-list) If my-list is nil, then the above expression will result in a list containing only the element some-value. Otherwise it

For example: (cons some-value my-list) If my-list is nil, then the above expression will result in a list containing only the element some-value. Otherwise it will be a list starting with some-value followed by any other values that have been previously in my-list.