import com.google.common.base.Function; import com.google.common.collect.FluentIterable; import com.google.common.collect.ImmutableMap; public class X { void m(Fluen<caret>tIterable<String> it, Function<String, String> f) { ImmutableMap<String, String> index = it.uniqueIndex(f); System.out.println(index.get("asd")); } }