Function choice_expectation 

#[doc(hidden)]
pub fn choice_expectation(
    choices: &[&str],
    aliases: &[MatchArgAlias],
    several: bool,
    suffix: &str,
) -> String

one of "fast", "slow"<suffix>, or one or more of "fast", "slow"<suffix> for a several_ok parameter (several), quoted as one_of quotes, the listed aliases between the choices and the suffix (one of "fast", "slow" (or "quick" for "fast"), or a number). The generated argument error of a match_arg / choices parameter on Either<T, R> passes the other accepted values as suffix (, or a data frame), in the words of its @param line; an Either whose arms both refused a value joins them with it too.