ruby
def logger=(logger)
  case logger
    when Logger then @logger = logger
    when false, nil then @logger = nil
  end
end

>> Mongoid.logger
#<ActiveSupport::BufferedLogger:0x3e99d48 @buffer={}, @guard=#<Mutex:0x3e99be0>, @log=#<File:/app/log/development.log>, @auto_flushing=1, @level=0>
>> Mongoid.logger = Logger.new($stdout) ; Mongoid.logger
#<ActiveSupport::BufferedLogger:0x3e99d48 @buffer={}, @guard=#<Mutex:0x3e99be0>, @log=#<File:/app/log/development.log>, @auto_flushing=1, @level=0>