private static Set<PsiJavaFile> prepareOperation(final UsageInfo @NotNull [] usages) {
    Set<PsiJavaFile> javaFiles = new HashSet<>();
    for (UsageInfo usage : usages) {
      if (usage.isNonCodeUsage) continue;
      final PsiFile file = usage.getFile();
      if (file instanceof PsiJavaFile) {
        javaFiles.add((PsiJavaFile)file);
      }
    }
    return javaFiles;
  }
private static Set<PsiJavaFile> prepareOperation(final UsageInfo @NotNull [] usages)