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Rust is a multi-paradigm programming language designed for
performance and safety, especially safe concurrency.
Rust is syntactically similar to C++, but can guarantee memory safety
by using a borrow checker to validate references.
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// unwrap_or_else() might be better becuase of eagerness
fn main() {
let _one = None.unwrap_or("one".to_string());
let _two = None.unwrap_or_else(|| "two".to_string());
}