* <p>To implement a multimap, a subclass must define the method {@link #createCollection()}, which
 * creates an empty collection of values for a key.
 *
 * <p>The multimap constructor takes a map that has a single entry for each distinct key. When you
 * insert a key-value pair with a key that isn't already in the multimap, {@code
 * AbstractMapBasedMultimap} calls {@link #createCollection()} to create the collection of values

      return new SampleElements<>(
          mapEntry(sampleKeys.e0(), createCollection(sampleValues.e0())),
          mapEntry(sampleKeys.e1(), createCollection(sampleValues.e1())),
          mapEntry(sampleKeys.e2(), createCollection(sampleValues.e2())),
          mapEntry(sampleKeys.e3(), createCollection(sampleValues.e3())),
          mapEntry(sampleKeys.e4(), createCollection(sampleValues.e4())));
    }

    @Override

    @Override
    public SampleElements<String> sampleValues() {
      return new SampleElements<>("january", "february", "march", "april", "may");
    }

    @Override
    public Collection<String> createCollection(Iterable<? extends String> values) {
      return Lists.newArrayList(values);
    }

    @Override
    public SampleElements<Entry<String, String>> samples() {
      return new SampleElements<>(

    @Override
    public SampleElements<String> sampleValues() {
      return new SampleElements<>("january", "february", "march", "april", "may");
    }

    @Override
    public Collection<String> createCollection(Iterable<? extends String> values) {
      return Lists.newArrayList(values);
    }

    @Override
    public SampleElements<Entry<String, String>> samples() {
      return new SampleElements<>(