ArgumentParser/Option.swift:82: Fatal error: Can't read a value from a parsable argument definition

I am new to Swift. I am using this library like this:

@main
final class Program: Options, ParsableCommand {
...
}

where

class Options {
@Option(name: [.customShort("w"), .long], help: "Image width (inches)")
var width: UInt = 24

@Option(name: [.customShort("h"), .long], help: "Image height (inches)")
var height: UInt = 24   

}

when I run my program I get this error:

ArgumentParser/Option.swift:82: Fatal error:


Can't read a value from a parsable argument definition.

This error indicates that a property declared with an @Argument,

@Option, @Flag, or @OptionGroup property wrapper was neither

initialized to a value nor decoded from command-line arguments.

To get a valid value, either call one of the static parsing methods

(parse, parseAsRoot, or main) or define an initializer that

initializes every property of your parsable type.


could anyone tell me what is the problem and how cn I fix it? thanks.