The add() list object variable method adds the specified string as a list element to the end of the list variable. The add() method does not remove or replace any other elements in the list.
$[ScriptVariable]::add(String str)
str (String): the string to add to the list variable.
The following example illustrates proper usage for the add() list method:
$recipients = "Engineering Group"
$recipients::add("Building 14")
$recipients::add("Winston Smythe")
print($recipients)
['Engineering Group']['Building 14']['Winston Smythe']
The above example defines a $recipient list variable. This variable is used throughout the list variable methods as a default example.