code: public PrecedenceOrderStep<ConfigFactory> withSources(
          NamedConfigSource firstSource,
          NamedConfigSource secondSource,
          NamedConfigSource... moreSources
      ) {
          return withSources(listOfTwoOrMore(
              firstSource,
              secondSource,
              moreSources
          ));
      }
docs: Replace all of this factory's {@link ConfigSource}s with
  {@code newSources}.
  
  <p>Example usage:</p>
  <pre>{@code
  ConfigFactory factory =
  ConfigFactory.emptyConfigFactory().bindDefaults()
  .withSources(
  ConfigFactory.classpathResource("application"),
  ConfigFactory.classpathResource("reference")
  ).fromHighestToLowestPrecedence();
  }</pre>