old_contents: """The vumi.application API."""
  
  __all__ = ["ApplicationWorker", "SessionManager"]
  
  from vumi.application.base import ApplicationWorker
  from vumi.application.session import SessionManager
  
new_contents: """The vumi.application API."""
  
  __all__ = ["ApplicationWorker", "SessionManager", "TagpoolManager"]
  
  from vumi.application.base import ApplicationWorker
  from vumi.application.session import SessionManager
  from vumi.application.tagpool import TagpoolManager
  
subject: Add TagpoolManager to vumi.application API.