code: protected function removeFromLookup($registry)
      {
          foreach ($this->lookup_pool as $idx => $reg) {
              if ($registry === $reg) {
                  if ($reg instanceof DelegatorAwareInterface) {
                      $reg->setDelegator();
                  }
                  unset($this->lookup_pool[$idx]);
              }
          }
          return $this;
      }
docs: Remove one registry from the pool
  
  @param  object $registry
  @return $this
  @access protected