Optional options

[usdaud]

[CommandOption("--memory")]
public long? Memory { get; set; }

I've tried like that

[CommandOption("--[memory]")]
public long? Memory { get; set; }

and

[CommandOption("[memory]")]
public long? Memory { get; set; }

and

[CommandOption("--memory")]
[DefaultValue(null)]
public long? Memory { get; set; }

Nothing works. How can make option optional?

[patriksvensson]

Could you elaborate what you're trying to achieve and what's not working. All options are optional by default.