LowerValue returns a pflag.Value interface with that will only accept values from a given list, but before checking the allowed list it will normalized values to lower-case.

MustBool returns the bool value of a flag with the given name, it will panic if the flag does not exists or is not the desired type.

MustInt returns the int value of a flag with the given name, it will panic if the flag does not exists or is not the desired type.

MustString returns the string value of a flag with the given name, it will panic if the flag does not exists or is not the desired type.

NormalizedValue returns a pflag.Value interface with that will only accept values from a given list, but before checking the allowed list it will normalized values to upper-case and remove any dash or hyphens.

UpperValue returns a pflag.Value interface with that will only accept values from a given list, but before checking the allowed list it will normalized values to upper-case.

Value returns a pflag.Value interface with that will only accept values from a given list.