The most simplest of doing error handling in rust is by returning `String` as a `Box<Error>`.
As you can see by running the example (the "Play" button in upper right of the code block), this only
prints out the last `Error`.
If the rust `main` function returns an Err(), this Err() will be displayed with `std::fmt::Debug`.
~~~rust
{{#include ../examples/tutorial1.rs:2:}}
~~~