code: public function detach(Runner $runner)
      {
          if (!$this->runners->contains($runner)) {
              throw new LogicException('Can\'t detach not attached runner.');
          }
  
          $this->runners->detach($runner);
  
          return $this;
      }
docs: Detaches a runner.
  
  @param Runner $runner
  
  @return $this