cdef extern from "Python.h":

    ############################################################################
    # 7.5.14 Set Objects
    ############################################################################

    # This section details the public API for set and frozenset
    # objects. Any functionality not listed below is best accessed
    # using the either the abstract object protocol (including
    # PyObject_CallMethod(), PyObject_RichCompareBool(),
    # PyObject_Hash(), PyObject_Repr(), PyObject_IsTrue(),
    # PyObject_Print(), and PyObject_GetIter()) or the abstract number
    # protocol (including PyNumber_Add(), PyNumber_Subtract(),
    # PyNumber_Or(), PyNumber_Xor(), PyNumber_InPlaceAdd(),
    # PyNumber_InPlaceSubtract(), PyNumber_InPlaceOr(), and
    # PyNumber_InPlaceXor()).

    # PySetObject
    # This subtype of PyObject is used to hold the internal data for
    # both set and frozenset objects. It is like a PyDictObject in
    # that it is a fixed size for small sets (much like tuple storage)
    # and will point to a separate, variable sized block of memory for
    # medium and large sized sets (much like list storage). None of
    # the fields of this structure should be considered public and are
    # subject to change. All access should be done through the
    # documented API rather than by manipulating the values in the
    # structure.

    # PyTypeObject PySet_Type
    # This is an instance of PyTypeObject representing the Python set type.

    # PyTypeObject PyFrozenSet_Type
    # This is an instance of PyTypeObject representing the Python frozenset type.

    # The following type check macros work on pointers to any Python
    # object. Likewise, the constructor functions work with any
    # iterable Python object.

    bint PyAnySet_Check(object p)
    # Return true if p is a set object, a frozenset object, or an
    # instance of a subtype.

    bint PyAnySet_CheckExact(object p)
    # Return true if p is a set object or a frozenset object but not
    # an instance of a subtype.

    bint PyFrozenSet_Check(object p)
    # Return true if p is a frozenset object or an instance of a subtype.

    bint PyFrozenSet_CheckExact(object p)
    # Return true if p is a frozenset object but not an instance of a subtype.

    bint PySet_Check(object p)
    # Return true if p is a set object or an instance of a subtype.

    object PySet_New(object iterable)
    # Return value: New reference.
    # Return a new set containing objects returned by the
    # iterable. The iterable may be NULL to create a new empty
    # set. Return the new set on success or NULL on failure. Raise
    # TypeError if iterable is not actually iterable. The constructor
    # is also useful for copying a set (c=set(s)).

    object PyFrozenSet_New(object iterable)
    # Return value: New reference.
    # Return a new frozenset containing objects returned by the
    # iterable. The iterable may be NULL to create a new empty
    # frozenset. Return the new set on success or NULL on
    # failure. Raise TypeError if iterable is not actually iterable.


    # The following functions and macros are available for instances
    # of set or frozenset or instances of their subtypes.

    Py_ssize_t PySet_Size(object anyset) except -1
    # Return the length of a set or frozenset object. Equivalent to
    # "len(anyset)". Raises a PyExc_SystemError if anyset is not a
    # set, frozenset, or an instance of a subtype.

    Py_ssize_t PySet_GET_SIZE(object anyset)
    # Macro form of PySet_Size() without error checking.

    bint PySet_Contains(object anyset, object key) except -1
    # Return 1 if found, 0 if not found, and -1 if an error is
    # encountered. Unlike the Python __contains__() method, this
    # function does not automatically convert unhashable sets into
    # temporary frozensets. Raise a TypeError if the key is
    # unhashable. Raise PyExc_SystemError if anyset is not a set,
    # frozenset, or an instance of a subtype.


    # The following functions are available for instances of set or
    # its subtypes but not for instances of frozenset or its subtypes.

    int PySet_Add(object set, object key) except -1
    # Add key to a set instance. Does not apply to frozenset
    # instances. Return 0 on success or -1 on failure. Raise a
    # TypeError if the key is unhashable. Raise a MemoryError if there
    # is no room to grow. Raise a SystemError if set is an not an
    # instance of set or its subtype.

    bint PySet_Discard(object set, object key) except -1
    # Return 1 if found and removed, 0 if not found (no action taken),
    # and -1 if an error is encountered. Does not raise KeyError for
    # missing keys. Raise a TypeError if the key is unhashable. Unlike
    # the Python discard() method, this function does not
    # automatically convert unhashable sets into temporary
    # frozensets. Raise PyExc_SystemError if set is an not an instance
    # of set or its subtype.

    object PySet_Pop(object set)
    # Return value: New reference.
    # Return a new reference to an arbitrary object in the set, and
    # removes the object from the set. Return NULL on failure. Raise
    # KeyError if the set is empty. Raise a SystemError if set is an
    # not an instance of set or its subtype.

    int PySet_Clear(object set)
    # Empty an existing set of all elements.