public static @NotNull File findSequentNonexistentFile(@NotNull File parentFolder, @NotNull @NonNls String filePrefix, @NotNull String extension) {
    return findSequentFile(parentFolder, filePrefix, extension, file -> !file.exists());
  }
public static @NotNull File findSequentNonexistentFile(@NotNull File parentFolder, @NotNull @NonNls String filePrefix, @NotNull String extension)