You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: database_event_spec.rb
    path of file: ./repos/coursemology2/spec/libraries
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
r
    
  def signal
    Thread.new do
      ActiveRecord::Base.connection_pool.with_connection do
        ActiveRecord::Base.signal(self.class::NOTIFICATION)
      end
    end
  end