framework/caching/Cache.php
protected function addValues($data, $duration)
    {
        $failedKeys = [];
        foreach ($data as $key => $value) {
            if ($this->addValue($key, $value, $duration) === false) {
                $failedKeys[] = $key;
            }
        }

        return $failedKeys;
    }
protected function addValues($data, $duration)
    {
        $failedKeys = [];
        foreach ($data as $key => $value) {
            if ($this->addValue($key, $value, $duration) === false) {
                $failedKeys[] = $key;
            }
        }

        return $failedKeys;
    }
Adds multiple key-value pairs to cache.
The default implementation calls [[addValue()]] multiple times add values one by one. If the underlying cache
storage supports multi-add, this method should be overridden to exploit that feature.
@param array $data array where key corresponds to cache key while value is the value stored.
@param int $duration the number of seconds in which the cached values will expire. 0 means never expire.
@return array array of failed keys