private static KeyValuePair<string, string> ParseSlashExplicitOption(string a)
{
var key = a.Contains(":") ? a.Substring(1, a.IndexOf(":") - 1).Trim() : a.Substring(1, a.Length - 1);
var value = a.Contains(":") ? a.Substring(a.IndexOf(":") + 1).Trim() : "";
if (key.Length == 0) throw new ArgException("Missing argument value after '/'");
return new KeyValuePair<string, string>(key, value);
}