Braintree\Configuration::__construct PHP Method

    public function __construct($attribs = [])
    {
        foreach ($attribs as $kind => $value) {
            if ($kind == 'environment') {
                CredentialsParser::assertValidEnvironment($value);
                $this->_environment = $value;
            }
            if ($kind == 'merchantId') {
                $this->_merchantId = $value;
            }
            if ($kind == 'publicKey') {
                $this->_publicKey = $value;
            }
            if ($kind == 'privateKey') {
                $this->_privateKey = $value;
            }
        }
        if (isset($attribs['clientId']) || isset($attribs['accessToken'])) {
            if (isset($attribs['environment']) || isset($attribs['merchantId']) || isset($attribs['publicKey']) || isset($attribs['privateKey'])) {
                throw new Exception\Configuration('Cannot mix OAuth credentials (clientId, clientSecret, accessToken) with key credentials (publicKey, privateKey, environment, merchantId).');
            }
            $parsedCredentials = new CredentialsParser($attribs);
            $this->_environment = $parsedCredentials->getEnvironment();
            $this->_merchantId = $parsedCredentials->getMerchantId();
            $this->_clientId = $parsedCredentials->getClientId();
            $this->_clientSecret = $parsedCredentials->getClientSecret();
            $this->_accessToken = $parsedCredentials->getAccessToken();
        }
    }