Braintree\OAuthGateway::_mapError PHP Method

    public function _mapError($result)
    {
        $error = $result->errors->deepAll()[0];
        if ($error->code == Error\Codes::OAUTH_INVALID_GRANT) {
            $result->error = 'invalid_grant';
        } else {
            if ($error->code == Error\Codes::OAUTH_INVALID_CREDENTIALS) {
                $result->error = 'invalid_credentials';
            } else {
                if ($error->code == Error\Codes::OAUTH_INVALID_SCOPE) {
                    $result->error = 'invalid_scope';
                }
            }
        }
        $result->errorDescription = explode(': ', $error->message)[1];
        return $result;
    }