如何将符号形式的Ruby哈希键递归转换为字符串

def convert_hash_keys(hash)
  hash.each_with_object({}) do |(key, value), result|
    # 将哈希键转换为字符串
    new_key = key.to_s
  
    # 如果哈希值是一个哈希，则递归调用转换方法
    new_value = value.is_a?(Hash) ? convert_hash_keys(value) : value
  
    result[new_key] = new_value
  end
end

hash = {
  name: 'John',
  age: 30,
  address: {
    city: 'New York',
    state: 'NY'
  }
}

converted_hash = convert_hash_keys(hash)
puts converted_hash

{
  "name"=>"John",
  "age"=>30,
  "address"=>{
    "city"=>"New York",
    "state"=>"NY"
  }
}