/// <summary>
 /// Adds the elements of another ExpressionCollection to the end of this ExpressionCollection.
 /// </summary>
 /// <param name="items">
 /// The ExpressionCollection whose elements are to be added to the end of this ExpressionCollection.
 /// </param>
 public void AddRange(ExpressionCollection items)
 {
     foreach (Expression item in items)
     {
         this.List.Add(item);
     }
 }
 /// <summary>
 /// Initializes a new instance of the ExpressionCollection class, containing elements
 /// copied from another instance of ExpressionCollection
 /// </summary>
 /// <param name="items">
 /// The ExpressionCollection whose elements are to be added to the new ExpressionCollection.
 /// </param>
 public ExpressionCollection(ExpressionCollection items)
 {
     this.AddRange(items);
 }
 public Enumerator(ExpressionCollection collection)
 {
     this.wrapped = ((System.Collections.CollectionBase)collection).GetEnumerator();
 }