```Python hl_lines="2"
{!../../docs_src/python_types/tutorial001.py!}
```

### Edítalo

Es un programa muy simple.

Ahora, imagina que lo estás escribiendo desde cero.

En algún punto habrías comenzado con la definición de la función, tenías los parámetros listos...

Pero, luego tienes que llamar "ese método que convierte la primera letra en una mayúscula".

Era `upper`? O era `uppercase`? `first_uppercase`? `capitalize`?

  }

  // retainAll(empty)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmpty() {
    expectReturnsFalse(empty);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmptyUnsupported() {
    expectReturnsFalseOrThrows(empty);

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveKeyRemovesFromInverse() {
    getMap().remove(k0());
    expectMissing(e0());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveKeyFromKeySetRemovesFromInverse() {
    getMap().keySet().remove(k0());
    expectMissing(e0());

tag will be omitted if its value is zero. If the field type has an `IsZero() bool`
method, that will be used to determine whether the value is zero. Otherwise, the
value is zero if it is [the zero value for its type](/ref/spec#The_zero_value).

If both `omitempty` and `omitzero` are specified, the field will be omitted if the

    }
    assertEquals(expectedSize, size2);
  }

  @CollectionSize.Require(ZERO)
  public void testIsEmptyYes() {
    assertTrue(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testIsEmptyNo() {
    assertFalse(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testSizeNullKey() {

academy.museum accenture accesscam.org accident-investigation.aero accident-prevention.aero accountant accountants acct.pro achi.nagano.jp aco act.au act.edu.au activetrail.biz actor ad ad.jp adachi.tokyo.jp adimo.co.uk adm.br adobeaemcloud.com adobeaemcloud.net adobeio-static.net adobeioruntime.net ads adult adult.ht adv.br adv.mz adygeya.ru adygeya.su ae ae.org aeg aejrie.no aero aero.mv aero.tt aerobatic.aero aeroclub.aero aerodrome.aero aeroport.fr aetna af affinitylottery.org.uk afjord.no afl africa...

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  public void testAddAtIndex_supportedPresent() {
    getList().add(0, e0());
    expectAdded(0, e0());
  }

  @ListFeature.Require(absent = SUPPORTS_ADD_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  /*
   * absent = ZERO isn't required, since unmodList.add() must
   * throw regardless, but it keeps the method name accurate.

cargo.aero
catering.aero
certification.aero
championship.aero
charter.aero
civilaviation.aero
club.aero
conference.aero
consultant.aero
consulting.aero
control.aero
council.aero
crew.aero
design.aero
dgca.aero
educator.aero
emergency.aero
engine.aero
engineer.aero
entertainment.aero
equipment.aero
exchange.aero
express.aero
federation.aero
flight.aero
fuel.aero
gliding.aero

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertFalse("contains(notPresent) should return false", collection.contains(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initCollectionWithNullElement();

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testFind_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertEquals(getMethodName() + "(notPresent) should return -1", -1, find(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testFind_nullContained() {
    initCollectionWithNullElement();