void (@NotNull PackagingElement<?> child) { this.update( () -> myChildren.remove(child), (builder, packagingElementEntity) -> { MutableExternalEntityMapping<PackagingElement<?>> mapping = builder.getMutableExternalMapping("intellij.artifacts.packaging.elements"); WorkspaceEntity entity = mapping.getFirstEntity(child); if (entity != null) { builder.removeEntity(entity); } } ); }