你好，
当我想要启用匿名模式时，遇到了 NoMethodError 错误。我使用的是 Discourse 2.5.1 版本（48d161e3b1）。
以下是日志内容：
消息（已报告 24 份副本）
NoMethodError（未定义方法 `<`，对象为 nil:NilClass）
/var/www/discourse/app/services/anonymous_shadow_creator.rb:34:in `get'
回溯
/var/www/discourse/app/services/anonymous_shadow_creator.rb:34:in `get'
/var/www/discourse/app/services/anonymous_shadow_creator.rb:11:in `get'
/var/www/discourse/app/controllers/users_controller.rb:863:in `toggle_anon'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/abstract_controller/base.rb:195:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/action_controller/metal/rendering.rb:30:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/abstract_controller/callbacks.rb:41:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.3.1/lib/action_controller/metal/rescue.rb:22:in `process_action'