pub fn new() -> Env {
        Env {
            entries: im::HashMap::new(),
        }
    }
/// Construct a new, empty environment.
Construct a new, empty environment.
Construct a new empty environment .
pub fn new() -> Env {
        Env {
            entries: im::HashMap::new(),
        }
    }
pub fn new ( ) -> Env { Env { entries : im :: HashMap :: new ( ) , } }
Construct a new, empty environment.
Construct a new empty environment .