pub trait NextTime {
fn next<Tz: TimeZone>(&self, from: &DateTime<Tz>) -> DateTime<Tz>;
fn prev<Tz: TimeZone>(&self, from: &DateTime<Tz>) -> DateTime<Tz>;
}
pub trait NextTime {
fn next<Tz: TimeZone>(&self, from: &DateTime<Tz>) -> DateTime<Tz>;
fn prev<Tz: TimeZone>(&self, from: &DateTime<Tz>) -> DateTime<Tz>;
}