code: def release_dynamips_id(self, project_id, dynamips_id):
          
          self._dynamips_ids.setdefault(project_id, set())
          if dynamips_id in self._dynamips_ids[project_id]:
              self._dynamips_ids[project_id].remove(dynamips_id)
docs: A Dynamips id can be reused by another VM
  
          :param project_id: UUID of the project
          :param dynamips_id: Asked id