我有一个存储在一个名为的实例变量中的字段哈希：
@series_from_fred
当我将此哈希传递给
Serial.create(@series_from_fred)
新的 Serial（模型名称）“行”被创建，散列中的参数映射到串行模型行中的字段。
但是，当我尝试通过
serial.update_attributes(@series_from_fred)
请注意，“串行”是
@serial.each do |serial|
我收到以下错误：
NoMethodError in AdminsController#checkSerials
undefined method `stringify_keys' for #<Array:0x007fd1fe3085e0>
有任何想法吗？
如果我进入 rails 控制台并输入“Serial”，就会发生这种情况
Serial(id: integer, series_name: string, realtime_start: string,
realtime_end: string, title: string, observation_start: string,
observation_end: string, frequency: string, frequency_short: string,
units: string, units_short: string, seasonal_adjustment: string,
seasonal_adjustment_short: string, last_updated: string, popularity: string,
notes: text, created_at: datetime, updated_at: datetime)
由于我在运行时从 api 获取数据，如果我进入 rails 控制台并输入“@series_from_fred”，我将返回“nil”。但是，使用 logger.info(@series_from_fred.to_s) 我可以在终端输出中“看到”@series_from_fred 的值。该输出是：
[{"realtime_start"=>"2013-02-28", "realtime_end"=>"2013-02-28",
"title"=>"Reserve Bank Credit - Securities Held Outright",
"observation_start"=>"1989-03-22", "observation_end"=>"2013-02-20",
"frequency"=>"Weekly, Ending Wednesday", "frequency_short"=>"W",
"units"=>"Billions of Dollars", "units_short"=>"Bil. of $",
"seasonal_adjustment"=>"Not Seasonally Adjusted", "seasonal_adjustment_short"=>"NSA",
"last_updated"=>"2013-02-22 08:32:54-06", "popularity"=>"47", "notes"=>"The amount of
securities held by Federal Reserve Banks. This quantity is the cumulative result of
permanent open market operations: outright purchases or sales of securities, conducted
by the Federal Reserve. Section 14 of the Federal Reserve Act defines the securities
that the Federal Reserve is authorized to buy and sell.", "series_name"=>"WSECOUT"}]