struct ImportantExcerpt<'a, 'b> {
    part_a: &'a str,
    part_b: &'b str,
}

impl<'c, 'd> ImportantExcerpt<'c, 'd> {
    // Some stuff
}

impl<'f> ImportantExcerpt<'f, 'f> {
    // Some different stuff
}

impl<'g, 'h: 'g> ImportantExcerpt<'g, 'h> {

}