def merge!(another)
      configs = self.configs
      another.each_pair do |key, value|
        if config = configs[key]
          config.set(receiver, value)
        else
          store[key] = value
        end
      end
      self
    end
def merge!(another)
      configs = self.configs
      another.each_pair do |key, value|
        if config = configs[key]
          config.set(receiver, value)
        else
          store[key] = value
        end
      end
      self
    end
Merges another with self.