src/AbstractMessage.php
final public function getFromListAt($fieldName, $index, $default = null)
    {
        $index = (int) $index;
        if (empty($this->data[$fieldName])
            || !is_array($this->data[$fieldName])
            || !isset($this->data[$fieldName][$index])
        ) {
            return $default;
        }
        return $this->data[$fieldName][$index];
    }
final public function getFromListAt($fieldName, $index, $default = null)
    {
        $index = (int) $index;
        if (empty($this->data[$fieldName])
            || !is_array($this->data[$fieldName])
            || !isset($this->data[$fieldName][$index])
        ) {
            return $default;
        }
        return $this->data[$fieldName][$index];
    }
{@inheritdoc}