docs: private void clearMarkers(List<WorkItem> files) throws CoreException {
          if (files == null) {
              project.deleteMarkers(FindBugsMarker.NAME, true, IResource.DEPTH_INFINITE);
              return;
          }
          for (WorkItem item : files) {
              if (item != null) {
                  item.clearMarkers();
              }
          }
      }