/// <summary>
/// Appends a sequence.
/// </summary>
/// <param name="ts">The sequence of elements to prepend.</param>
/// <returns>The random access sequence consisting of
/// this random access sequence and elements of <paramref name="ts"/>.</returns>
public RandomAccessSequence <T> AppendRange(IEnumerable <T> ts)
{
return(new RandomAccessSequence <T>(_ft.AppendRange(ts.Map(t => new Element(t)))));
}
