Function trailing_series

pub fn trailing_series<C, I, S, O, P>(
    input: &mut Pear<I>,
    item: P,
    seperator: S,
) -> Result<C, I>
where
    C: Collection<O>,
    I: Input,
    S: Token<I> + Clone,
    P: FnMut(&mut Pear<I>) -> Result<O, I>,

Parses many separator delimited ps with an optional trailing separator. Gramatically, this is:

item (SEPERATOR item)* SEPERATOR?