}
  }

  // Insert a new empty block, setting the bookkeeping to sentinel values
  // in order to update them as appropriate.
  auto new_entry = std::make_shared<Block>();
  lru_list_.push_front(key);
  lra_list_.push_front(key);
  new_entry->lru_iterator = lru_list_.begin();
  new_entry->lra_iterator = lra_list_.begin();
  new_entry->timestamp = timer_seconds_();
  block_map_.emplace(std::make_pair(key, new_entry));

      cache_.erase(it);
      return false;
    }
    *value = it->second.value;
    lru_list_.push_front(it->first);
    it->second.lru_iterator = lru_list_.begin();
    return true;
  }

  void InsertLocked(const std::string& key, const T& value)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_) {
    lru_list_.push_front(key);
    Entry entry{timer_seconds_(), value, lru_list_.begin()};

pkg container/list, method (*List) MoveToFront(*Element)
pkg container/list, method (*List) PushBack(interface{}) *Element
pkg container/list, method (*List) PushBackList(*List)
pkg container/list, method (*List) PushFront(interface{}) *Element
pkg container/list, method (*List) PushFrontList(*List)
pkg container/list, method (*List) Remove(*Element) interface{}
pkg container/list, type Element struct