code: public static boolean containsVault(Path pathToVault, String masterkeyFilename) {
  		Path masterKeyPath = pathToVault.resolve(masterkeyFilename);
  		Path dataDirPath = pathToVault.resolve(Constants.DATA_DIR_NAME);
  		return Files.isReadable(masterKeyPath) && Files.isDirectory(dataDirPath);
  	}
docs: Checks if the folder represented by the given path exists and contains a valid vault structure.
  
  @param pathToVault A directory path
  @param masterkeyFilename Name of the masterkey file
  @return <code>true</code> if the directory seems to contain a vault.
  @since 1.1.0