code: public Module build() {
      return new AbstractModule() {
        @Override
        protected void configure() {
          Multibinder<ConfigurationSource> multiBinder =
              Multibinder.newSetBinder(binder(), ConfigurationSource.class);
          for (ConfigurationSource configurationSource : configurationSources) {
            multiBinder.addBinding().toInstance(configurationSource);
          }
        }
      };
    }
docs: Builds the {@link ConfigurationSourcesModuleBuilder} with the list of
  {@link ConfigurationSource}s built using the {@link ConfigurationSourcesModuleBuilder
  #addSource(ConfigurationSource)} builder method.
  
  @return a Guice module that configures a Multibinder for ConfigurationSources