def largest_hash_key(hash)
  key = hash.sort{|a,b| a[1] <=> b[1]}.last
  puts key
end

hash = { "n" => 100,"m" => 100,"y" => 300,"d" => 200,"a" => 0 }
largest_hash_key(hash)

在此代码中,“puts”打印最大的键和值e.x y300.
那么,我如何修改代码以找到最大值并将其键入to_s变量？