AddItems is a method used to append an existing collection of email addresses to the current collection. AList represents the collection with TIdEmailAddressItem instances to append to the current collection items. When AList is empty (when the collection Count in AList contains 0), no action is performed. 

AddItems iterates over the TIdEmailAddressItem instances in the AList collection, and creates a item in the current collection by calling the Add method. The value of the new collection item is set by calling Assign using the collection item in AList as an argument. 

Use methods in the ancestor class to maintain Items in the collection, like Delete, Clear, or Destroy.

TIdEmailAddressItem