/// <summary>
/// Retrieves the maximum key and the associated value.
/// </summary>
/// <returns>The tuple of the maximum key, associated value and the
/// dictionary containing all other elements, if the dictionary is
/// non-empty; <c>None</c> otherwise.</returns>
public Optional <Tuple <TKey, TValue> > MaxKeyAndValue()
{
if (Count == 0)
{
return(Optional <Tuple <TKey, TValue> > .None);
}
if (Count == 1)
{
return(Optional.Some(Tuple.New(_key, _value)));
}
return(_right.MaxKeyAndValue());
}
