Error message

Warning: Attempt to read property "value" on null in lazarski_page_attachments_alter() (line 49 of themes/lazarski/lazarski.theme).
lazarski_page_attachments_alter() (Line: 458)
Drupal\Core\Theme\ThemeManager->alterForTheme() (Line: 467)
Drupal\Core\Theme\ThemeManager->alter() (Line: 320)
Drupal\Core\Render\MainContent\HtmlRenderer->invokePageAttachmentHooks() (Line: 285)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 284)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 128)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray()
call_user_func() (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch() (Line: 186)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 201)
Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
Drupal\Core\DrupalKernel->handle() (Line: 19)
Anna Borowska portret