* powerSet(ImmutableSet.of(1, 2))} returns the set {@code {{}, {1}, {2}, {1, 2}}}.
   *
   * <p>Elements appear in these subsets in the same iteration order as they appeared in the input
   * set. The order in which these subsets appear in the outer set is undefined. Note that the power
   * set of the empty set is not the empty set, but a one-element set containing the empty set.
   *

        final Map<String, Object> doc = new LinkedHashMap<>();
        doc.put("url", "https://example.com/page.html");
        doc.put("title", "Test");
        doc.put("content", "Body");
        doc.put("cache", "should appear");

        final SearchEngineClient searchEngineClient = new SearchEngineClient() {
            @Override

    TF_ImportGraphDefResults* results, int* num_opers, TF_Operation*** opers);

// Fetches any input mappings requested via
// TF_ImportGraphDefOptionsAddInputMapping() that didn't appear in the GraphDef
// and weren't used as input to any node in the imported graph def. The number
// of fetched mappings is returned in `num_missing_unused_input_mappings`. The