SimplePie::set_useragent( string $ua = null ): void

1370    public function set_useragent(?string $ua = null)1371    {1372        if ($this->http_client_injected) {1373            throw new SimplePieException(sprintf(1374                'Using "%s()" has no effect, because you already provided a HTTP client with "%s::set_http_client()". Configure user agent string in your HTTP client instead.',1375                __METHOD__,1376                self::class1377            ));1378        }1379 1380        if ($ua === null) {1381            $ua = Misc::get_default_useragent();1382        }1383 1384        $this->useragent = (string) $ua;1385 1386        // Reset a possible existing FileClient,1387        // so a new client with the changed value will be created1388        if (is_object($this->http_client) && $this->http_client instanceof FileClient) {1389            $this->http_client = null;1390        } elseif (is_object($this->http_client)) {1391            // Trigger notice if a PSR-18 client was set1392            trigger_error(sprintf(1393                'Using "%s()" has no effect, because you already provided a HTTP client with "%s::set_http_client()". Configure the useragent in your HTTP client instead.',1394                __METHOD__,1395                get_class($this)1396            ), \E_USER_NOTICE);1397        }1398    }