private static @Nullable Set<@NotNull PsiElement> getPsiElements(@NotNull Collection<TaintNode> toAnnotate) {
    Set<PsiElement> psiElements = new HashSet<>();
    for (TaintNode node : toAnnotate) {
      PsiElement psiElement = node.getPsiElement();
      if (psiElement == null) return null;
      if (psiElement instanceof PsiLocalVariable) continue;
      psiElements.add(psiElement);
    }
    return psiElements;
  }
private static @Nullable Set<@NotNull PsiElement> getPsiElements(@NotNull Collection<TaintNode> toAnnotate)