code: def unregister_a_problem(self, prob):
          
          self.source_problems.remove(prob.uuid)
  
          # For know if we are still an impact, maybe our dependencies
          # are not aware of the remove of the impact state because it's not ordered
          # so we can just look at if we still have some problem in our list
          if not self.source_problems:
              self.is_impact = False
              # No more an impact, we can unset the impact state
              self.unset_impact_state()
  
          # And we register a new broks for update status
          self.broks.append(self.get_update_status_brok())
docs: Remove the problem from our problems list
          and check if we are still 'impacted'
  
          :param prob: problem to remove
          :type prob: alignak.objects.schedulingitem.SchedulingItem
          :return: None