TODO

Item Summary
Name	Type	Multiplicity	Description
reference	property string	[0,1]	Identifier of existing activity before/after which the current one has to be inserted.
activity	container ActivityDefinitionType	[0,-1]	Activity or activities that are to be inserted.

Items
- reference
  
  Flags: RAM,runtime
  
  Multiplicity: [0,1]
  
  Identifier of existing activity before/after which the current one has to be inserted. Null means the first or the last one, respectively.
- activity
  
  Flags: elaborate,RAM,runtime
  
  Multiplicity: [0,-1]
  
  Activity or activities that are to be inserted.