Set<String> (@NotNull PsiMethod method, @Nullable LanguageLevel preferredFormat) { final Set<String> signatures = new LinkedHashSet<>(); if (preferredFormat != null) signatures.add(formatMethodSignature(method, preferredFormat)); signatures.add(formatMethodSignature(method, LanguageLevel.JDK_10)); signatures.add(formatMethodSignature(method, LanguageLevel.JDK_1_8)); signatures.add(formatMethodSignature(method, LanguageLevel.JDK_1_5)); return signatures; }