code: public static ConfigSourceName configSourceNamed(final String name) {
  
          checkNotNull(name);
  
          return new ConfigSourceName() {
  
              @Override
              public String toString() {
                  return name;
              }
  
              @Override
              public String name() {
                  return name;
              }
          };
      }
docs: A simple {@link ConfigSourceName} instance that can be useful for
  referring to config sources.
  
  <p>Example usage:</p>
  <pre>{@code
  // add a config source with lower precedence than one named "apple"
  ConfigFactory insertLowerThanApple(
  ConfigFactory factory,
  NameConfigSource sourceToInsert) {
  
  return factory
  .insertSource(sourceToInsert)
  .withLowerPrecedenceThan(configSourceNamed("apple"))
  }}</pre>