php 7.4

[yabushraber]

I am getting this error in php7.4, can you please fix:
Deprecated: array_key_exists(): Using array_key_exists() on objects is deprecated. Use isset() or property_exists() instead

in Riskified\DecisionNotification\Model\Notification::parse_body at line 94
if (!array_key_exists('order', $body))
throw new Exception\BadPostJsonException($this->headers, $this->body)

thank you