# Objetos tipo

type PyTypeObject
  Part of the Stable ABI (as an opaque struct).

  La estructura C de los objetos utilizados para describir los tipos incorporados.

PyTypeObject PyType_Type
  Part of the Stable ABI.

  Este es el objeto tipo para objetos tipo; es el mismo objeto que `type` en la capa Python.

int PyType_Check(PyObject *o)

  Retorna un valor distinto de cero si el objeto o es un objeto tipo, incluidas las instancias de tipos derivados del objeto de tipo estándar. Retorna 0 en todos los demás casos. Esta función siempre finaliza con éxito.

int PyType_CheckExact(PyObject *o)

  Retorna un valor distinto de cero si el objeto o es un objeto tipo, pero no un subtipo del objeto tipo estándar. Retorna 0 en todos los demás casos. Esta función siempre finaliza con éxito.

unsigned int PyType_ClearCache()
  Part of the Stable ABI.

  Borra la caché de búsqueda interna. Retorna la etiqueta (tag) de la versión actual.

  Distinto en la versión 3.16: This function is now a no-op as the type cache is now implemented per-type. It still returns the current version tag.

unsigned long PyType_GetFlags(PyTypeObject *type)
  Part of the Stable ABI.

  Retorna el miembro `tp_flags` de type. Esta función está destinada principalmente para su uso con `Py_LIMITED_API`; se garantiza que los bits de bandera individuales serán estables en las versiones de Python, pero el acceso a `tp_flags` en sí mismo no forma parte de la API limitada.

  Added in version 3.2.

  Distinto en la versión 3.4: El tipo de retorno es ahora `unsigned long` en vez de `long`.

PyObject *PyType_GetDict(PyTypeObject *type)

  Retorna el espacio de nombres interno del objeto tipo, que de otra manera solo está expuesto a través de un proxy de solo lectura (`cls.__dict__`). Esto es un reemplazo para acceder a `tp_dict` directamente. El diccionario retornado debe tratarse como de solo lectura.

  Esta función está destinada a casos específicos de incrustación y vinculación de lenguajes, donde el acceso directo al diccionario es necesario y el acceso indirecto (por ejemplo, a través del proxy o `PyObject_GetAttr()`) no es adecuado.

  Los módulos de extensión deben continuar usando `tp_dict`, directa o indirectamente, al configurar sus propios tipos.

  Added in version 3.12.

void PyType_Modified(PyTypeObject *type)
  Part of the Stable ABI.

  Invalida la memoria caché de búsqueda interna para el tipo y todos sus subtipos. Esta función debe llamarse después de cualquier modificación manual de los atributos o clases base del tipo.

int PyType_AddWatcher(PyType_WatchCallback callback)

  Registra callback como un observador de tipo. Retorna un ID entero no negativo que debe pasarse a llamadas futuras a `PyType_Watch()`. En caso de error (por ejemplo, no hay más IDs de observador disponibles), retorna `-1` y establece una excepción.

  In free-threaded builds, `PyType_AddWatcher()` is not thread-safe, so it must be called at start up (before spawning the first thread).

  Added in version 3.12.

int PyType_ClearWatcher(int watcher_id)

  Borra el observador identificado por watcher_id (previamente retornado de `PyType_AddWatcher()`). Retorna `0` en caso de éxito, `-1` en caso de error (por ejemplo, si watcher_id nunca fue registrado).

  Una extensión nunca debe llamar a `PyType_ClearWatcher` con un watcher_id que no le fue retornado por una llamada previa a `PyType_AddWatcher()`.

  Added in version 3.12.

int PyType_Watch(int watcher_id, PyObject *type)

  Marca type como observado. El retrollamada (callback) otorgado watcher_id por `PyType_AddWatcher()` será llamado cada vez que `PyType_Modified()` reporte un cambio a type. (El callback puede ser llamado solo una vez para una serie de modificaciones consecutivas a type, si `_PyType_Lookup()` no es llamado en type entre las modificaciones; esto es un detalle de implementación y sujeto a cambios).

  The callback is also invoked when a watched heap type is deallocated.

  Una extensión nunca debe llamar a `PyType_Watch` con un watcher_id que no le fue retornado por una llamada previa a `PyType_AddWatcher()`.

  Added in version 3.12.

  Distinto en la versión 3.15: The callback is now also invoked when a watched heap type is deallocated.

int PyType_Unwatch(int watcher_id, PyObject *type)

  Mark type as not watched. This undoes a previous call to `PyType_Watch()`. type must not be `NULL`.

  An extension should never call this function with a watcher_id that was not returned to it by a previous call to `PyType_AddWatcher()`.

  On success, this function returns `0`. On failure, this function returns `-1` with an exception set.

  Added in version 3.12.

typedef int (*PyType_WatchCallback)(PyObject *type)

  Tipo de una función de retrollamada (callback) de observador de tipo.

  El retrollamada (callback) no debe modificar type o causar que `PyType_Modified()` sea llamado en type o cualquier tipo en su MRO; violar esta regla podría causar recursión infinita.

  The callback may be called during type deallocation. In this case, the type object is temporarily resurrected (its reference count is at least 1) and all its attributes are still valid. However, the callback should not store new strong references to the type, as this would resurrect the object and prevent its deallocation.

  Added in version 3.12.

  Distinto en la versión 3.15: The callback may now be called during deallocation of a watched heap type.

int PyType_HasFeature(PyTypeObject *o, int feature)

  Retorna un valor distinto de cero si el tipo objeto o establece la característica feature. Las características de tipo se indican mediante flags de un solo bit.

int PyType_FastSubclass(PyTypeObject *type, int flag)

  Return non-zero if the type object type sets the subclass flag flag. Subclass flags are denoted by `Py_TPFLAGS_*_SUBCLASS`. This function is used by many `_Check` functions for common types.

  Ver también

  `PyObject_TypeCheck()`, which is used as a slower alternative in `_Check` functions for types that don’t come with subclass flags.

int PyType_IS_GC(PyTypeObject *o)

  Retorna verdadero si el objeto tipo incluye soporte para el detector de ciclos; esto prueba el indicador de tipo `Py_TPFLAGS_HAVE_GC`.

int PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)
  Part of the Stable ABI.

  Retorna verdadero si a es un subtipo de b.

  Esta función solo busca subtipos reales, lo que significa que `__subclasscheck__()` no se llama en b. Llama `PyObject_IsSubclass()` para hacer la misma verificación que `issubclass()` haría.

PyObject *PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)
  Return value: New reference. Part of the Stable ABI.

  Generic handler for the `tp_alloc` slot of a type object. Uses Python’s default memory allocation mechanism to allocate memory for a new instance, zeros the memory, then initializes the memory as if by calling `PyObject_Init()` or `PyObject_InitVar()`.

  Do not call this directly to allocate memory for an object; call the type’s `tp_alloc` slot instead.

  For types that support garbage collection (i.e., the `Py_TPFLAGS_HAVE_GC` flag is set), this function behaves like `PyObject_GC_New` or `PyObject_GC_NewVar` (except the memory is guaranteed to be zeroed before initialization), and should be paired with `PyObject_GC_Del()` in `tp_free`. Otherwise, it behaves like `PyObject_New` or `PyObject_NewVar` (except the memory is guaranteed to be zeroed before initialization) and should be paired with `PyObject_Free()` in `tp_free`.

PyObject *PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
  Return value: New reference. Part of the Stable ABI.

  Generic handler for the `tp_new` slot of a type object. Creates a new instance using the type’s `tp_alloc` slot and returns the resulting object.

int PyType_Ready(PyTypeObject *type)
  Part of the Stable ABI.

  Finalizar un objeto tipo. Se debe llamar a todos los objetos tipo para finalizar su inicialización. Esta función es responsable de agregar ranuras heredadas de la clase base de un tipo. Retorna `0` en caso de éxito o retorna `-1` y establece una excepción en caso de error.

  Nota

  Si algunas de las clases base implementan el protocolo GC y el tipo proporcionado no incluye `Py_TPFLAGS_HAVE_GC` en sus banderas, entonces el protocolo GC se implementará automáticamente desde sus padres. Por el contrario, si el tipo que se está creando incluye `Py_TPFLAGS_HAVE_GC` en sus banderas, entonces debe implementar el protocolo GC por sí mismo implementando al menos el manejador `tp_traverse`.

PyObject *PyType_GetName(PyTypeObject *type)
  Return value: New reference. Part of the Stable ABI since version 3.11.

  Retorna el nombre del tipo. Equivalente a obtener el atributo `__name__` del tipo.

  Added in version 3.11.

PyObject *PyType_GetQualName(PyTypeObject *type)
  Return value: New reference. Part of the Stable ABI since version 3.11.

  Retorna el nombre calificado del tipo. Equivalente a obtener el atributo `__qualname__` del tipo.

  Added in version 3.11.

PyObject *PyType_GetFullyQualifiedName(PyTypeObject *type)
  Part of the Stable ABI since version 3.13.

  Retorna el nombre completamente calificado del tipo. Equivalente a `f"{type.__module__}.{type.__qualname__}"`, o `type.__qualname__` si `type.__module__` no es una cadena de caracteres o es igual a `"builtins"`.

  Added in version 3.13.

PyObject *PyType_GetModuleName(PyTypeObject *type)
  Part of the Stable ABI since version 3.13.

  Retorna el nombre del módulo del tipo. Equivalente a obtener el atributo `type.__module__`.

  Added in version 3.13.

void *PyType_GetSlot(PyTypeObject *type, int slot)
  Part of the Stable ABI since version 3.4.

  Retorna el puntero de función almacenado en la ranura dada. Si el resultado es `NULL`, esto indica que la ranura es `NULL` o que la función se llamó con parámetros no válidos. Las personas que llaman suelen convertir el puntero de resultado en el tipo de función apropiado.

  Consulte `PyType_Slot.slot` para conocer los posibles valores del argumento slot.

  Added in version 3.4.

  Distinto en la versión 3.10: `PyType_GetSlot()` ahora puede aceptar todos los tipos. Anteriormente, estaba limitado a heap types.

PyObject *PyType_GetModule(PyTypeObject *type)
  Return value: Borrowed reference. Part of the Stable ABI since version 3.10.

  Retorna el objeto módulo asociado con el tipo dado cuando se creó el tipo usando `PyType_FromModuleAndSpec()`.

  The returned reference is borrowed from type, and will be valid as long as you hold a reference to type. Do not release it with `Py_DECREF()` or similar.

  Si no hay ningún módulo asociado con el tipo dado, establece `TypeError` y retorna `NULL`.

  This function is usually used to get the module in which a method is defined. Note that in such a method, `PyType_GetModule(Py_TYPE(self))` may not return the intended result. `Py_TYPE(self)` may be a subclass of the intended class, and subclasses are not necessarily defined in the same module as their superclass. See `PyCMethod` to get the class that defines the method. See `PyType_GetModuleByToken()` for cases when `PyCMethod` cannot be used.

  Added in version 3.9.

void *PyType_GetModuleState(PyTypeObject *type)
  Part of the Stable ABI since version 3.10.

  Retorna el estado del objeto de módulo asociado con el tipo dado. Este es un atajo para llamar `PyModule_GetState()` en el resultado de `PyType_GetModule()`.

  Si no hay ningún módulo asociado con el tipo dado, establece `TypeError` y retorna `NULL`.

  Si el tipo type tiene un módulo asociado pero su estado es `NULL`, retorna `NULL` sin establecer una excepción.

  Added in version 3.9.

PyObject *PyType_GetModuleByToken(PyTypeObject *type, const void *mod_token)
  Return value: New reference. Part of the Stable ABI since version 3.15.

  Find the first superclass whose module has the given module token, and return that module.

  Si no se encuentra ningún módulo, lanza `TypeError` y retorna `NULL`.

  Esta función está pensada para ser utilizada junto con `PyModule_GetState()` para obtener el estado del módulo de los métodos de ranura (como `tp_init` o `nb_add`) y en otros lugares donde la clase que define a un método no se puede pasar utilizando la convención de llamada `PyCMethod`.

  Added in version 3.15.

PyObject *PyType_GetModuleByDef(PyTypeObject *type, struct PyModuleDef *def)
  Return value: Borrowed reference. Part of the Stable ABI since version 3.13.

  Find the first superclass whose module was created from the given `PyModuleDef` def, or whose module token is equal to def, and return that module.

  Note that modules created from a `PyModuleDef` always have their token set to the `PyModuleDef`’s address. In other words, this function is equivalent to `PyType_GetModuleByToken()`, except that it:

  - returns a borrowed reference, and

  - has a non-`void*` argument type (which is a cosmetic difference in C).

  The returned reference is borrowed from type, and will be valid as long as you hold a reference to type. Do not release it with `Py_DECREF()` or similar.

  Added in version 3.11.

int PyType_GetBaseByToken(PyTypeObject *type, void *tp_token, PyTypeObject **result)
  Part of the Stable ABI since version 3.14.

  Find the first superclass in type’s method resolution order whose `Py_tp_token` token is equal to tp_token.

  - If found, set *result to a new strong reference to it and return `1`.

  - If not found, set *result to `NULL` and return `0`.

  - On error, set *result to `NULL` and return `-1` with an exception set.

  The result argument may be `NULL`, in which case *result is not set. Use this if you need only the return value.

  The tp_token argument may not be `NULL`.

  Added in version 3.14.

int PyUnstable_Type_AssignVersionTag(PyTypeObject *type)
  This is Unstable API. It may change without warning in minor releases.

  Intenta asignar una etiqueta (tag) de versión al tipo dado.

  Retorna 1 si el tipo ya tenía una etiqueta (tag) de versión válida o se asignó una nueva, o 0 si no se pudo asignar una nueva etiqueta.

  Added in version 3.12.

int PyType_SUPPORTS_WEAKREFS(PyTypeObject *type)

  Return true if instances of type support creating weak references, false otherwise. This function always succeeds. type must not be `NULL`.

  Ver también

  - Objetos de referencia débil

  - `weakref`

## Crear tipos asignados en montículo (heap)

The following function is used to create heap types:

PyObject *PyType_FromSlots(const PySlot *slots)
  Part of the Stable ABI since version 3.15.

  Create and return a heap type from a `PySlot` array. See Definition slots for general information on slots, and Type slot IDs for slots specific to type creation.

  Esta función llama `PyType_Ready()` en el tipo nuevo.

  Nota que esta función no coincide completamente con el comportamiento de llamar `type()` o usar la sentencia `class`. Con tipos base o metaclases proporcionados por el usuario, prefiera llamar `type` (o la metaclase) sobre las funciones `PyType_From*`. Específicamente:

  - `__new__()` no es llamado en la nueva clase (y debe ser establecido a `type.__new__`).

  - `__init__()` no es llamado en la nueva clase.

  - `__init_subclass__()` no es llamado en ninguna base.

  - `__set_name__()` no es llamado en nuevos descriptores.

  Slots are typically defined as a global static constant arrays. However, sometimes slot values are not statically known at compile time. For example, slots like `Py_tp_bases`, `Py_tp_metaclass` and `Py_tp_module` require live Python objects. In this case, it is recommended to put such slots on the stack, and use `Py_slot_subslots` to refer to an array of static slots. For example:

      static const PySlot my_slots[] = {
         PySlot_STATIC_DATA(Py_tp_name, "MyClass"),
         PySlot_FUNC(Py_tp_repr, my_repr_func),
         ...
         PySlot_END
      };

      PyObject *make_my_class(PyObject *module) {
         PySlot all_slots[] = {
            PySlot_STATIC_DATA(Py_slot_subslots, my_slots),
            PySlot_DATA(Py_tp_module, module),
            PySlot_END
         };
         return PyType_FromSlots(all_slots);
      }

Heap types created without the `Py_TPFLAGS_IMMUTABLETYPE` flag may be modified, for example by setting attributes on them, as with classes defined in Python code. Sometimes, such modifications are necessary to fully initialize a type, but you may wish to prevent users from changing the type after the initialization is done:

int PyType_Freeze(PyTypeObject *type)
  Part of the Stable ABI since version 3.14.

  Make a type immutable: set the `Py_TPFLAGS_IMMUTABLETYPE` flag.

  All base classes of type must be immutable.

  On success, return `0`. On error, set an exception and return `-1`.

  The type must not be used before it’s made immutable. For example, type instances must not be created before the type is made immutable.

  Added in version 3.14.

### Type slot IDs

Most type slot IDs are named like the field names of the structures `PyTypeObject`, `PyNumberMethods`, `PySequenceMethods`, `PyMappingMethods` and `PyAsyncMethods` with an added `Py_` prefix. For example, use:

- `Py_tp_dealloc` to set `PyTypeObject.tp_dealloc`

- `Py_nb_add` to set `PyNumberMethods.nb_add`

- `Py_sq_length` to set `PySequenceMethods.sq_length`

The following slots need additional considerations when specified as slots:

- `Py_tp_name`

- `Py_tp_basicsize` and `Py_tp_extra_basicsize`

- `Py_tp_itemsize`

- `Py_tp_flags`

Additional slots do not directly correspond to a `PyTypeObject` struct field:

- `Py_tp_token`

- `Py_tp_metaclass`

- `Py_tp_module`

The following “offset” fields cannot be set using `PyType_Slot`:

- `tp_weaklistoffset` (use `Py_TPFLAGS_MANAGED_WEAKREF` en su lugar si es posible)

- `tp_dictoffset` (use `Py_TPFLAGS_MANAGED_DICT` en su lugar si es posible)

- `tp_vectorcall_offset` (use `"__vectorcalloffset__"` en PyMemberDef)

If it is not possible to switch to a `MANAGED` flag (for example, for vectorcall or to support Python older than 3.12), specify the offset in `Py_tp_members`. See PyMemberDef documentation for details.

The following internal fields cannot be set at all when creating a heap type:

- `tp_dict`, `tp_mro`, `tp_cache`, `tp_subclasses`, and `tp_weaklist`.

The `Py_tp_base` slot is equivalent to `Py_tp_bases`; both may be set either to a type or a tuple of types. If both are specified, the value of `Py_tp_bases` is used.

Slot values may not be `NULL`, except for the following:

- `Py_tp_doc`

- `Py_tp_token` (for clarity, prefer `Py_TP_USE_SPEC` rather than `NULL`)

Distinto en la versión 3.9: Las ranuras en `PyBufferProcs` se pueden configurar en la API ilimitada.

Distinto en la versión 3.11: `bf_getbuffer` y `bf_releasebuffer` ahora están disponibles bajo la API limitada.

Distinto en la versión 3.14: The field `tp_vectorcall` can now be set using `Py_tp_vectorcall`. See the field’s documentation for details.

Distinto en la versión 3.15: The `Py_tp_bases` slot may be set to a single type object, making it equivalent to the `Py_tp_base` slot. Previously, a tuple of types was required.

The following slots correspond to fields in the underlying type structure, but need extra remarks for use as slots:

Py_tp_name
  Part of the Stable ABI since version 3.15.

  `Slot ID` for the name of the type, used to set `PyTypeObject.tp_name`.

  This slot (or `PyType_Spec.name`) is required to create a type.

  This may not be used in `PyType_Spec.slots`. Use `PyType_Spec.name` instead.

  Detalles de implementación de CPython: CPython processes slots in order. It is recommended to put `Py_tp_name` at the beginning of the slots array, so that if processing of a later slots fails, error messages can include the name.

  Added in version 3.15.

Py_tp_basicsize
  Part of the Stable ABI since version 3.15.

  `Slot ID` for the size of the instance in bytes. It is used to set `PyTypeObject.tp_basicsize`.

  The value must be positive.

  This may not be used in `PyType_Spec.slots`. Use `PyType_Spec.basicsize` instead.

  This slot may not be used with `PyType_GetSlot()`. Use `PyTypeObject.tp_basicsize` instead if needed, but be aware that a type’s size is often considered an implementation detail.

  Added in version 3.15.

Py_tp_extra_basicsize
  Part of the Stable ABI since version 3.15.

  `Slot ID` for type data size in bytes, that is, how much space instances of the class need in addition to space needed for superclasses.

  The value is used, together with the size of superclasses, to set `PyTypeObject.tp_basicsize`. Python will insert padding as needed to meet `tp_basicsize`’s alignment requirements.

  Use `PyObject_GetTypeData()` to get a pointer to subclass-specific memory reserved this way.

  The value must be positive. To specify that instances need no additional size (that is, size should be inherited), omit the `Py_tp_extra_basicsize` slot rather than set it to zero.

  Specifying both `Py_tp_basicsize` and `Py_tp_extra_basicsize` is an error.

  This may not be used in `PyType_Spec.slots`. Use negative `PyType_Spec.basicsize` instead.

  This slot may not be used with `PyType_GetSlot()`.

  Added in version 3.15.

Py_tp_itemsize
  Part of the Stable ABI since version 3.15.

  `Slot ID` for the size of one element of a variable-size type, in bytes. Used to set `PyTypeObject.tp_itemsize`. See `tp_itemsize` documentation for caveats.

  The value must be positive.

  If this slot is missing, `tp_itemsize` is inherited. Extending arbitrary variable-sized classes is dangerous, since some types use a fixed offset for variable-sized memory, which can then overlap fixed-sized memory used by a subclass. To help prevent mistakes, inheriting `itemsize` is only possible in the following situations:

  - The base is not variable-sized (its `tp_itemsize` is zero).

  - El `PyType_Spec.basicsize` solicitado es positivo, sugiriendo que la distribución de memoria de la clase base es conocida.

  - El `PyType_Spec.basicsize` solicitado es cero, sugiriendo que la subclase no accede a la memoria de la instancia directamente.

  - Con la bandera `Py_TPFLAGS_ITEMS_AT_END`.

  This may not be used in `PyType_Spec.slots`. Use `PyType_Spec.itemsize` instead.

  This slot may not be used with `PyType_GetSlot()`.

  Added in version 3.15.

Py_tp_flags
  Part of the Stable ABI since version 3.15.

  `Slot ID` for type flags, used to set `PyTypeObject.tp_flags`.

  The `Py_TPFLAGS_HEAPTYPE` flag is not set, `PyType_FromSpecWithBases()` sets it automatically.

  This may not be used in `PyType_Spec.slots`. Use negative `PyType_Spec.basicsize` instead.

  This slot may not be used with `PyType_GetSlot()`. Use `PyType_GetFlags()` instead.

  Added in version 3.15.

Py_tp_bases
  Part of the Stable ABI.

  `Slot ID` for type flags, used to set `PyTypeObject.tp_bases`.

  The slot can be set to a tuple of type objects which the newly created type should inherit from, like the «positional arguments» of a Python class definition.

  Alternately, the slot can be set to a single type object to specify a single base. The effect is the same as specifying a one-element tuple.

  Distinto en la versión 3.15: Previously, `Py_tp_bases` required a tuple of types.

Py_tp_base
  Part of the Stable ABI.

  Equivalent to `Py_tp_bases` (with `s` at the end). If both are specified, `Py_tp_bases` takes priority and this slot is ignored.

  Distinto en la versión 3.15: Previously, `Py_tp_base` required a single type, not a tuple.

  Soft deprecated since version 3.15: When not targeting older Python versions, prefer `Py_tp_bases`.

The following slots do not correspond to public fields in the underlying structures:

Py_tp_metaclass
  Part of the Stable ABI since version 3.15.

  `Slot ID` for the metaclass used to construct the resulting type object. When omitted the metaclass is derived from bases (`Py_tp_bases` or the bases argument of `PyType_FromMetaclass()`).

  Metaclasses that override `tp_new` are not supported, except if `tp_new` is `NULL`.

  This may not be used in `PyType_Spec.slots`. Use `PyType_FromMetaclass()` to specify a metaclass with `PyType_Spec`.

  This slot may not be used with `PyType_GetSlot()`. Use `Py_TYPE()` on the type object instead.

  Added in version 3.15.

Py_tp_module
  Part of the Stable ABI since version 3.15.

  `Slot ID` for recording the module in which the new class is defined.

  The value must be a module object. The module is associated with the new type and can later be retrieved with `PyType_GetModule()`. The associated module is not inherited by subclasses; it must be specified for each class individually.

  This may not be used in `PyType_Spec.slots`. Use `PyType_FromMetaclass()` to specify a module with `PyType_Spec`.

  This slot may not be used with `PyType_GetSlot()`. Use `PyType_GetModule()` instead.

  Added in version 3.15.

Py_tp_token
  Part of the Stable ABI since version 3.14.

  `Slot ID` for recording a static memory layout ID for a class.

  If the class is defined using a `PyType_Spec`, and that spec is statically allocated, the token can be set to the spec using the special value `Py_TP_USE_SPEC`:

      static PyType_Slot foo_slots[] = {
         {Py_tp_token, Py_TP_USE_SPEC},

  It can also be set to an arbitrary pointer, but you must ensure that:

  - The pointer outlives the class, so it’s not reused for something else while the class exists.

  - It «belongs» to the extension module where the class lives, so it will not clash with other extensions.

  Use `PyType_GetBaseByToken()` to check if a class’s superclass has a given token – that is, check whether the memory layout is compatible.

  To get the token for a given class (without considering superclasses), use `PyType_GetSlot()` with `Py_tp_token`.

  Added in version 3.14.

  Py_TP_USE_SPEC
    Part of the Stable ABI since version 3.14.

    Used as a value with `Py_tp_token` to set the token to the class’s `PyType_Spec`. May only be used for classes defined using `PyType_Spec`.

    Expands to `NULL`.

    Added in version 3.14.

Py_tp_slots
  Part of the Stable ABI since version 3.15.

  `Slot ID` that works like `Py_slot_subslots`, except it specifies an array of `PyType_Slot` structures.

  Added in version 3.15.

## Soft-deprecated API

The following functions are soft deprecated. They will continue to work, but new features will be added as slots for `PyType_FromSlots()`, not as arguments to new `PyType_From*` functions.

PyObject *PyType_FromMetaclass(PyTypeObject *metaclass, PyObject *module, PyType_Spec *spec, PyObject *bases)
  Part of the Stable ABI since version 3.12.

  Crea y retorna un tipo heap a partir del spec (ver `Py_TPFLAGS_HEAPTYPE`).

  A non-`NULL` metaclass argument corresponds to the `Py_tp_metaclass` slot.

  A non-`NULL` bases argument corresponds to the `Py_tp_bases` slot, and takes precedence over `Py_tp_bases` and `Py_tp_bases` slots.

  A non-`NULL` module argument corresponds to the `Py_tp_module` slot.

  Esta función llama `PyType_Ready()` en el tipo nuevo.

  Note that this function does not fully match the behavior of calling `type()` or using the `class` statement. See the note in `PyType_FromSlots()` documentation for details.

  Added in version 3.12.

  Soft deprecated since version 3.16.0a0 (unreleased): Prefer `PyType_FromSlots()` in new code.

PyObject *PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
  Return value: New reference. Part of the Stable ABI since version 3.10.

  Equivalente a `PyType_FromMetaclass(NULL, module, spec, bases)`.

  Added in version 3.9.

  Distinto en la versión 3.10: La función ahora acepta una sola clase como argumento bases y `NULL` como ranura `tp_doc`.

  Distinto en la versión 3.12: La función ahora encuentra y usa una metaclase correspondiente a las clases base proporcionadas. Anteriormente, sólo se retornaban instancias de `type`.

  The `tp_new` of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides `tp_new` is deprecated.

  Distinto en la versión 3.14: Creating classes whose metaclass overrides `tp_new` is no longer allowed.

  Soft deprecated since version 3.16.0a0 (unreleased): Prefer `PyType_FromSlots()` in new code.

PyObject *PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases)
  Return value: New reference. Part of the Stable ABI since version 3.3.

  Equivalente a `PyType_FromMetaclass(NULL, NULL, spec, bases)`.

  Added in version 3.3.

  Distinto en la versión 3.12: La función ahora encuentra y usa una metaclase correspondiente a las clases base proporcionadas. Anteriormente, sólo se retornaban instancias de `type`.

  The `tp_new` of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides `tp_new` is deprecated.

  Distinto en la versión 3.14: Creating classes whose metaclass overrides `tp_new` is no longer allowed.

  Soft deprecated since version 3.16.0a0 (unreleased): Prefer `PyType_FromSlots()` in new code.

PyObject *PyType_FromSpec(PyType_Spec *spec)
  Return value: New reference. Part of the Stable ABI.

  Equivalente a `PyType_FromMetaclass(NULL, NULL, spec, NULL)`.

  Distinto en la versión 3.12: La función ahora encuentra y usa una metaclase correspondiente a las clases base proporcionadas en las ranuras Py_tp_base[s]. Anteriormente, sólo se retornaban instancias de `type`.

  The `tp_new` of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides `tp_new` is deprecated.

  Distinto en la versión 3.14: Creating classes whose metaclass overrides `tp_new` is no longer allowed.

  Soft deprecated since version 3.16.0a0 (unreleased): Prefer `PyType_FromSlots()` in new code.

type PyType_Spec
  Part of the Stable ABI (including all members).

  Structure defining a type’s behavior, used for soft-deprecated functions like `PyType_FromMetaclass()`.

  This structure contains several members that can instead be specified as slots for `PyType_FromSlots()`, and an array of slot entries with a simpler structure.

  const char *name

    Corresponds to `Py_tp_name`.

  int basicsize

    If positive, corresponds to `Py_tp_basicsize`.

    If negative, corresponds to `Py_tp_extra_basicsize` set to the absolute value.

    Distinto en la versión 3.12: Anteriormente, este campo no podía ser negativo.

  int itemsize

    Corresponds to `Py_tp_itemsize`.

  unsigned int flags

    Corresponds to `Py_tp_flags`.

  PyType_Slot *slots

    Array of `PyType_Slot` (not `PySlot`) structures.

    Terminated by the special slot value `{0, NULL}`. Each slot ID should be specified at most once.

    type PyType_Slot
      Part of the Stable ABI (including all members).

      Structure defining optional functionality of a type, used for soft-deprecated functions like `PyType_FromMetaclass()`.

      Note that a `PyType_Slot` array may be included in a `PySlot` array using `Py_tp_slots`, and vice versa using `Py_slot_subslots`.

      Each `PyType_Slot` structure `tpslot` is interpreted as the following `PySlot` structure:

          (PySlot){
             .sl_id=tpslot.slot,
             .sl_flags=PySlot_INTPTR | sub_static,
             .sl_ptr=tpslot.func
          }

      where `sub_static` is `PySlot_STATIC` if the slot requires the flag (such as for `Py_tp_methods`), or if this flag is present on the «parent» `Py_tp_slots` slot (if any).

      int slot

        Corresponds to `PySlot.sl_id`.

      void *pfunc

        Corresponds to `PySlot.sl_ptr`.