# Introduction In this lab, we will explore the usage of `impl Trait` in Rust, which can be used as an argument type or a return type, simplifying function declarations and allowing for more flexible and concise code. > **Note:** If the lab does not specify a file name, you can use any file name you want. For example, you can use `main.rs`, compile and run it with `rustc main.rs && ./main`.
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