def each
      return to_enum unless block_given?
      each_explicit_key do |*key|
        next if default?(*key)
        yield key, get(*key)
      end
    end
def each
      return to_enum unless block_given?
      each_explicit_key do |*key|
        next if default?(*key)
        yield key, get(*key)
      end
    end
Expensive. Use only for debug