pub fn new(lower: Antichain<Time>, upper: Antichain<Time>) -> Self {
        assert!(!lower.elements().is_empty()); // this should always be true.
                                               // assert!(upper.len() > 0);           // this may not always be true.
        Description { lower, upper }
    }
/// Returns a new description from its component parts.
Returns a new description from its component parts.
Returns a new description from its component parts .
pub fn new(lower: Antichain<Time>, upper: Antichain<Time>) -> Self {
        assert!(!lower.elements().is_empty()); // this should always be true.
                                               // assert!(upper.len() > 0);           // this may not always be true.
        Description { lower, upper }
    }
pub fn new ( lower : Antichain < Time > , upper : Antichain < Time > ) -> Self { assert ! ( lower elements ( ) is_empty ( ) ) ; // this should always be true. // assert!(upper.len() > 0);           // this may not always be true. Description { lower , upper } }
Returns a new description from its component parts.
Returns a new description from its component parts .
lower
Antichain<Time>
upper
Antichain<Time>