Function route_vec_path 

pub fn route_vec_path<'a, 'k, I>(
    name: &'a str,
    my_prefix: &str,
    field_name: &str,
    inner_prefix: &str,
    natural_keys: I,
) -> VecRoute<'a>
where
    I: IntoIterator<Item = (usize, &'k str)>,