WP_REST_Templates_Controller::create_item( WP_REST_Request $request ): WP_REST_Response|WP_Error

448	public function create_item( $request ) {449		$prepared_post = $this->prepare_item_for_database( $request );450 451		if ( is_wp_error( $prepared_post ) ) {452			return $prepared_post;453		}454 455		$prepared_post->post_name = $request['slug'];456		$post_id                  = wp_insert_post( wp_slash( (array) $prepared_post ), true );457		if ( is_wp_error( $post_id ) ) {458			if ( 'db_insert_error' === $post_id->get_error_code() ) {459				$post_id->add_data( array( 'status' => 500 ) );460			} else {461				$post_id->add_data( array( 'status' => 400 ) );462			}463 464			return $post_id;465		}466		$posts = get_block_templates( array( 'wp_id' => $post_id ), $this->post_type );467		if ( ! count( $posts ) ) {468			return new WP_Error( 'rest_template_insert_error', __( 'No templates exist with that id.' ), array( 'status' => 400 ) );469		}470		$id            = $posts[0]->id;471		$post          = get_post( $post_id );472		$template      = get_block_template( $id, $this->post_type );473		$fields_update = $this->update_additional_fields_for_object( $template, $request );474		if ( is_wp_error( $fields_update ) ) {475			return $fields_update;476		}477 478		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php */479		do_action( "rest_after_insert_{$this->post_type}", $post, $request, true );480 481		wp_after_insert_post( $post, false, null );482 483		$response = $this->prepare_item_for_response( $template, $request );484		$response = rest_ensure_response( $response );485 486		$response->set_status( 201 );487		$response->header( 'Location', rest_url( sprintf( '%s/%s/%s', $this->namespace, $this->rest_base, $template->id ) ) );488 489		return $response;490	}