private static Collection<PsiElement> group(@NotNull SliceNode node, @NotNull Map<SliceNode, NullAnalysisResult> nulls, int group) {
    return nulls.get(node).groupedByValue[group];
  }
private static Collection<PsiElement> group(@NotNull SliceNode node, @NotNull Map<SliceNode, NullAnalysisResult> nulls, int group)