code: public static XmlConfigurationSource create(Reader reader)
        throws ConfigurationException, IOException {
      return new XmlConfigurationSource(createConfiguration(reader), DEFAULT_PRIORITY);
    }
docs: Creates an instance of {@link XmlConfigurationSource}.
  
  @throws ConfigurationException when fails to create the {@link XMLConfiguration}
  @throws IOException when fails to read from the {@code reader}
  @throws NullPointerException if the path to the xml file is null