error: the trait `core::str::pattern::DoubleEndedSearcher<'_>` is not
implemented for the type `core::str::pattern::StrSearcher<'_, '_>` [E0277]
for part in "1:30".split(":").rev() {

let mut length = 0;
let mut mult = 1;
for part in "1:30".split(":").rev() {
   length += mult * part.parse::<i32>().unwrap();
   mult *= 60;
}

impl<'a, P> DoubleEndedIterator for Split<'a, P> where P: Pattern<'a>, P::Searcher: DoubleEndedSearcher<'a>

impl<'a, P> DoubleEndedIterator for Split<'a, P>
where P: Pattern<'a>, P::Searcher: DoubleEndedSearcher<'a>

impl<'a, 'b> Pattern<'a> for &'b str

type Searcher = StrSearcher<'a, 'b>