PayPal\Core\PPCredentialManager::initCredential PHP Method

    private function initCredential($config)
    {
        $suffix = 1;
        $prefix = "acct";
        if (array_key_exists($prefix, $config)) {
            $credArr = $this->config[$searchKey];
        } else {
            $arr = array();
            foreach ($config as $k => $v) {
                if (strstr($k, $prefix)) {
                    $arr[$k] = $v;
                }
            }
            $credArr = $arr;
        }
        $arr = array();
        foreach ($config as $key => $value) {
            $pos = strpos($key, '.');
            if (strstr($key, "acct")) {
                $arr[] = substr($key, 0, $pos);
            }
        }
        $arrayPartKeys = array_unique($arr);
        if (count($arrayPartKeys) == 0) {
            throw new PPMissingCredentialException("No valid API accounts have been configured");
        }
        $key = $prefix . $suffix;
        while (in_array($key, $arrayPartKeys)) {
            if (isset($credArr[$key . ".Signature"]) && $credArr[$key . ".Signature"] != null && $credArr[$key . ".Signature"] != "") {
                $userName = isset($credArr[$key . '.UserName']) ? $credArr[$key . '.UserName'] : "";
                $password = isset($credArr[$key . '.Password']) ? $credArr[$key . '.Password'] : "";
                $signature = isset($credArr[$key . '.Signature']) ? $credArr[$key . '.Signature'] : "";
                $this->credentialHashmap[$userName] = new PPSignatureCredential($userName, $password, $signature);
                if (isset($credArr[$key . '.AppId'])) {
                    $this->credentialHashmap[$userName]->setApplicationId($credArr[$key . '.AppId']);
                }
            } elseif (isset($credArr[$key . ".CertPath"]) && $credArr[$key . ".CertPath"] != null && $credArr[$key . ".CertPath"] != "") {
                $userName = isset($credArr[$key . '.UserName']) ? $credArr[$key . '.UserName'] : "";
                $password = isset($credArr[$key . '.Password']) ? $credArr[$key . '.Password'] : "";
                $certPassPhrase = isset($credArr[$key . '.CertKey']) ? $credArr[$key . '.CertKey'] : "";
                $certPath = isset($credArr[$key . '.CertPath']) ? $credArr[$key . '.CertPath'] : "";
                $this->credentialHashmap[$userName] = new PPCertificateCredential($userName, $password, $certPath, $certPassPhrase);
                if (isset($credArr[$key . '.AppId'])) {
                    $this->credentialHashmap[$userName]->setApplicationId($credArr[$key . '.AppId']);
                }
            } elseif (isset($credArr[$key . ".ClientId"]) && isset($credArr[$key . ".ClientId"])) {
                $userName = $key;
                $this->credentialHashmap[$userName] = array('clientId' => $credArr[$key . ".ClientId"], 'clientSecret' => $credArr[$key . ".ClientSecret"]);
            }
            if ($userName && isset($credArr[$key . ".Subject"]) && trim($credArr[$key . ".Subject"]) != "") {
                $this->credentialHashmap[$userName]->setThirdPartyAuthorization(new PPSubjectAuthorization($credArr[$key . ".Subject"]));
            } else {
                if ($userName && (isset($credArr[$key . '.accessToken']) && isset($credArr[$key . '.tokenSecret']))) {
                    $this->credentialHashmap[$userName]->setThirdPartyAuthorization(new PPTokenAuthorization($credArr[$key . '.accessToken'], $credArr[$key . '.tokenSecret']));
                }
            }
            if ($userName && $this->defaultAccountName == null) {
                if (array_key_exists($key . '.UserName', $credArr)) {
                    $this->defaultAccountName = $credArr[$key . '.UserName'];
                } else {
                    $this->defaultAccountName = $key;
                }
            }
            $suffix++;
            $key = $prefix . $suffix;
        }
    }