pub fn new() -> Env<T> {
        Env {
            entries: im::Vector::new(),
        }
    }
/// Create a new, empty environment.
Create a new, empty environment.
Create a new empty environment .
pub fn new() -> Env<T> {
        Env {
            entries: im::Vector::new(),
        }
    }
pub fn new ( ) -> Env < T > { Env { entries : im :: Vector :: new ( ) , } }
Create a new, empty environment.
Create a new empty environment .