22877eb0__Services___O_Reilly_Broadcast_Table_3__Command_Pipes_Command
[Description] Executes an operation (typically contained in a group), and if the operation throws an exception, invokes a contained "catch" element. This is the primary error catching mechanism for XProc. [Command] 
try
XProc: Drupal, XML Pipelines and RESTful Services - O'Reilly Broadcast
Command