Used for immutable dereferencing operations, like `*v`.| doc.rust-lang.org
`Result` is a type that represents either success (`Ok`) or failure (`Err`).| doc.rust-lang.org
A trait for giving a type a useful default value.| doc.rust-lang.org
Parse a value from a string| doc.rust-lang.org
The `Option` type. See the module level documentation for more.| doc.rust-lang.org