///

### Krok 2: utwórz instancję `FastAPI`

{*../../docs_src/first_steps/tutorial001.py hl[3] *}

Zmienna `app` będzie tutaj "instancją" klasy `FastAPI`.

Będzie to główny punkt interakcji przy tworzeniu całego interfejsu API.

Ta zmienna `app` jest tą samą zmienną, do której odnosi się `uvicorn` w poleceniu:

<div class="termy">

```console
$ uvicorn main:app --reload

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

    Multimap<String, Integer> toPut = LinkedListMultimap.create();
    toPut.put("foo", 1);
    toPut.put("bar", 4);
    toPut.put("foo", 2);
    toPut.put("foo", 1);
    toPut.put("bar", 5);
    Multimap<String, Integer> moreToPut = LinkedListMultimap.create();
    moreToPut.put("foo", 6);
    moreToPut.put("bar", 4);
    moreToPut.put("foo", 7);
    moreToPut.put("foo", 2);

    map.put("foo", 1);
    map.put("bar", 2);
    map.put("bar", 3);
    assertEquals("{foo=[1], bar=[2, 3]}", map.toString());
    assertEquals("[foo=1, bar=2, bar=3]", map.entries().toString());
  }

  public void testLinkedPutOutOfOrder() {
    Multimap<String, Integer> map = create();
    map.put("bar", 1);
    map.put("foo", 2);
    map.put("bar", 3);

    multimap.put("bar", 2);
    multimap.put("bar", null);
    multimap.put("foo", null);
    multimap.put("foo", 4);
    multimap.put(null, -1);
    multimap.put("bar", 3);
    multimap.put("bar", 1);
    multimap.put("foo", 1);

    assertEquals(
        "{foo=[3, -1, 2, null, 4, 1], null=[null, 0, -1], bar=[1, 2, null, 3]}",
        multimap.toString());
  }

  public void testPutMultimapOrdered() {

    Multimap<String, Integer> toPut = LinkedListMultimap.create();
    toPut.put("foo", 1);
    toPut.put("bar", 4);
    toPut.put("foo", 2);
    toPut.put("foo", 1);
    toPut.put("bar", 5);
    Multimap<String, Integer> moreToPut = LinkedListMultimap.create();
    moreToPut.put("foo", 6);
    moreToPut.put("bar", 4);
    moreToPut.put("foo", 7);
    moreToPut.put("foo", 2);

        result.put(NameMappers.STATIC_NAME, NameMappers.staticNameMapper());
        result.put(NameMappers.GAV_NAME, NameMappers.gavNameMapper());
        result.put(NameMappers.DISCRIMINATING_NAME, NameMappers.discriminatingNameMapper());
        result.put(NameMappers.FILE_GAV_NAME, NameMappers.fileGavNameMapper());
        result.put(NameMappers.FILE_HGAV_NAME, NameMappers.fileHashingGavNameMapper());

    Map<String, Integer> underlying = Maps.newLinkedHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    underlying.put("d", 4);
    underlying.put("e", 5);
    underlying.put("f", 6);
    underlying.put("g", 7);
    Map<String, String> map = transformValues(underlying, Functions.toStringFunction());

    map.remove("a");

  }

  public void testFilterFiltered() {
    Multimap<String, Integer> unfiltered = HashMultimap.create();
    unfiltered.put("foo", 55556);
    unfiltered.put("badkey", 1);
    unfiltered.put("foo", 1);
    Multimap<String, Integer> keyFiltered = filterKeys(unfiltered, KEY_PREDICATE);
    Multimap<String, Integer> filtered = filterValues(keyFiltered, VALUE_PREDICATE);
    assertEquals(1, filtered.size());

    Map<String, Integer> underlying = Maps.newLinkedHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    underlying.put("d", 4);
    underlying.put("e", 5);
    underlying.put("f", 6);
    underlying.put("g", 7);
    Map<String, String> map = transformValues(underlying, Functions.toStringFunction());

    map.remove("a");