code: def cleanup(self):
          
          remove = []
          for handle, assoc in self.assocs.iteritems():
              if assoc.getExpiresIn() == 0:
                  remove.append(handle)
          for handle in remove:
              del self.assocs[handle]
          return len(remove), len(self.assocs)
docs: Remove expired associations.
  
          @return: tuple of (removed associations, remaining associations)