docs: public static File getBaseDir(final List<File> files) {
          String common = getCommonPrefix(files.stream().map(new Function<File, String>() {
              @Override
              public String apply(final File file) {
                  return file.getAbsolutePath();
              }
          }).collect(Collectors.toList()));
          if (null != common) {
              return new File(common);
          }
          return null;
      }