PHP - Mailchimp api key verification function

 The string should be composed of two parts separated by a dash/minus:
1) an md5 string
2) a variable string with the "data center" subdomain name.

 This function checks if the api key is (somewhat) correct.


    private function isApiKeyValid($api_key){
        return !empty( preg_match('#^[a-z0-9]{32}-[a-z0-9]{3,}$#i', $api_key) );
    }