Sequence Protocol
*****************

int PySequence_Check(PyObject *o)

   Return "1" if the object provides sequence protocol, and "0"
   otherwise. This function always succeeds.

Py_ssize_t PySequence_Size(PyObject *o)
Py_ssize_t PySequence_Length(PyObject *o)

   Returns the number of objects in sequence *o* on success, and "-1"
   on failure. For objects that do not provide sequence protocol, this
   is equivalent to the Python expression "len(o)".

PyObject* PySequence_Concat(PyObject *o1, PyObject *o2)
    *Return value: New reference.*

   Return the concatenation of *o1* and *o2* on success, and *NULL* on
   failure. This is the equivalent of the Python expression "o1 + o2".

PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count)
    *Return value: New reference.*

   Return the result of repeating sequence object *o* *count* times,
   or *NULL* on failure.  This is the equivalent of the Python
   expression "o * count".

PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2)
    *Return value: New reference.*

   Return the concatenation of *o1* and *o2* on success, and *NULL* on
   failure. The operation is done *in-place* when *o1* supports it.
   This is the equivalent of the Python expression "o1 += o2".

PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count)
    *Return value: New reference.*

   Return the result of repeating sequence object *o* *count* times,
   or *NULL* on failure.  The operation is done *in-place* when *o*
   supports it.  This is the equivalent of the Python expression "o *=
   count".

PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i)
    *Return value: New reference.*

   Return the *i*th element of *o*, or *NULL* on failure. This is the
   equivalent of the Python expression "o[i]".

PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)
    *Return value: New reference.*

   Return the slice of sequence object *o* between *i1* and *i2*, or
   *NULL* on failure. This is the equivalent of the Python expression
   "o[i1:i2]".

int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v)

   Assign object *v* to the *i*th element of *o*.  Raise an exception
   and return "-1" on failure; return "0" on success.  This is the
   equivalent of the Python statement "o[i] = v".  This function *does
   not* steal a reference to *v*.

   If *v* is *NULL*, the element is deleted, however this feature is
   deprecated in favour of using "PySequence_DelItem()".

int PySequence_DelItem(PyObject *o, Py_ssize_t i)

   Delete the *i*th element of object *o*.  Returns "-1" on failure.
   This is the equivalent of the Python statement "del o[i]".

int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v)

   Assign the sequence object *v* to the slice in sequence object *o*
   from *i1* to *i2*.  This is the equivalent of the Python statement
   "o[i1:i2] = v".

int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)

   Delete the slice in sequence object *o* from *i1* to *i2*.  Returns
   "-1" on failure.  This is the equivalent of the Python statement
   "del o[i1:i2]".

Py_ssize_t PySequence_Count(PyObject *o, PyObject *value)

   Return the number of occurrences of *value* in *o*, that is, return
   the number of keys for which "o[key] == value".  On failure, return
   "-1".  This is equivalent to the Python expression
   "o.count(value)".

int PySequence_Contains(PyObject *o, PyObject *value)

   Determine if *o* contains *value*.  If an item in *o* is equal to
   *value*, return "1", otherwise return "0". On error, return "-1".
   This is equivalent to the Python expression "value in o".

Py_ssize_t PySequence_Index(PyObject *o, PyObject *value)

   Return the first index *i* for which "o[i] == value".  On error,
   return "-1".    This is equivalent to the Python expression
   "o.index(value)".

PyObject* PySequence_List(PyObject *o)
    *Return value: New reference.*

   Return a list object with the same contents as the sequence or
   iterable *o*, or *NULL* on failure.  The returned list is
   guaranteed to be new.  This is equivalent to the Python expression
   "list(o)".

PyObject* PySequence_Tuple(PyObject *o)
    *Return value: New reference.*

   Return a tuple object with the same contents as the arbitrary
   sequence *o* or *NULL* on failure.  If *o* is a tuple, a new
   reference will be returned, otherwise a tuple will be constructed
   with the appropriate contents.  This is equivalent to the Python
   expression "tuple(o)".

PyObject* PySequence_Fast(PyObject *o, const char *m)
    *Return value: New reference.*

   Return the sequence *o* as a list, unless it is already a tuple or
   list, in which case *o* is returned.  Use
   "PySequence_Fast_GET_ITEM()" to access the members of the result.
   Returns *NULL* on failure.  If the object is not a sequence, raises
   "TypeError" with *m* as the message text.

PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)
    *Return value: Borrowed reference.*

   Return the *i*th element of *o*, assuming that *o* was returned by
   "PySequence_Fast()", *o* is not *NULL*, and that *i* is within
   bounds.

PyObject** PySequence_Fast_ITEMS(PyObject *o)

   Return the underlying array of PyObject pointers.  Assumes that *o*
   was returned by "PySequence_Fast()" and *o* is not *NULL*.

   Note, if a list gets resized, the reallocation may relocate the
   items array. So, only use the underlying array pointer in contexts
   where the sequence cannot change.

PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i)
    *Return value: New reference.*

   Return the *i*th element of *o* or *NULL* on failure. Macro form of
   "PySequence_GetItem()" but without checking that
   "PySequence_Check()" on *o* is true and without adjustment for
   negative indices.

Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)

   Returns the length of *o*, assuming that *o* was returned by
   "PySequence_Fast()" and that *o* is not *NULL*.  The size can also
   be gotten by calling "PySequence_Size()" on *o*, but
   "PySequence_Fast_GET_SIZE()" is faster because it can assume *o* is
   a list or tuple.
