code: def clear_candidates(self, clear_env=True):
          
          async def slave_task(addr):
              r_manager = await self.env.connect(addr)
              return await r_manager.clear_candidates()
  
          self._candidates = []
          if clear_env:
              if self._single_env:
                  self.env.clear_candidates()
              else:
                  mgrs = self.get_managers()
                  run(create_tasks(slave_task, mgrs))
docs: Clear the current candidates.
  
          :param bool clear_env:
              If ``True``, clears also environment's (or its underlying slave
              environments') candidates.