# File lib/hashie/extensions/stringify_keys.rb, line 45
        def stringify_keys!(hash)
          hash.extend(Hashie::Extensions::StringifyKeys) unless hash.respond_to?(:stringify_keys!)
          hash.keys.each do |k| # rubocop:disable Performance/HashEachMethods
            stringify_keys_recursively!(hash[k])
            hash[k.to_s] = hash.delete(k)
          end
          hash
        end