/// <inheritdoc/>
public OptionSchema Add(
string name,
char?shortName,
string argumentName,
string description,
Action <RequiredArgumentOption> action)
{
CheckName(name);
CheckShortName(shortName);
CheckDuplication(name, shortName);
var spec = new RequiredArgumentOptionSpec(
name, shortName, argumentName, description, action);
return(new OptionSchemaImpl(all.Append(spec)));
}