Type Alias ArgResult 

pub type ArgResult<T> = Result<Option<T>, String>;

Ok(None) = absent, Ok(Some(v)) = present and usable, Err = present but not convertible to the declared type.

Aliased Type

pub enum ArgResult<T> {
    Ok(Option<T>),
    Err(String),
}

Variants

Ok(Option<T>)

Contains the success value

Err(String)

Contains the error value