def each_pair # :yields: key, value
      configs.each_pair do |key, config|
        yield(key, config.get(receiver))
      end
      
      store.each_pair do |key, value|
        yield(key, value)
      end
    end
def each_pair # :yields: key, value
      configs.each_pair do |key, config|
        yield(key, config.get(receiver))
      end
      
      store.each_pair do |key, value|
        yield(key, value)
      end
    end
Calls block once for each key-value pair stored in self.