@NotNull
  public static String getDefaultBaseName(final Collection<? extends PropertiesFile> files) {
    String commonPrefix = null;
    for (PropertiesFile file : files) {
      final String baseName = file.getVirtualFile().getNameWithoutExtension();
      if (commonPrefix == null) {
        commonPrefix = baseName;
      } else {
        commonPrefix = StringUtil.commonPrefix(commonPrefix, baseName);
        if (commonPrefix.isEmpty()) {
          break;
        }
      }
    }
    assert commonPrefix != null;
    if (!commonPrefix.isEmpty() && BASE_NAME_BORDER_CHAR.contains(commonPrefix.charAt(commonPrefix.length() - 1))) {
      commonPrefix = commonPrefix.substring(0, commonPrefix.length() - 1);
    }
    return commonPrefix;
  }
@NotNull
  public static String getDefaultBaseName(final Collection<? extends PropertiesFile> files)