Issue #26778: Fixed "a/an/and" typos in code comment and documentation.
diff --git a/Doc/c-api/set.rst b/Doc/c-api/set.rst
index 258530b..f6ebcf3 100644
--- a/Doc/c-api/set.rst
+++ b/Doc/c-api/set.rst
@@ -140,7 +140,7 @@
Add *key* to a :class:`set` instance. Does not apply to :class:`frozenset`
instances. Return 0 on success or -1 on failure. Raise a :exc:`TypeError` if
the *key* is unhashable. Raise a :exc:`MemoryError` if there is no room to grow.
- Raise a :exc:`SystemError` if *set* is an not an instance of :class:`set` or its
+ Raise a :exc:`SystemError` if *set* is not an instance of :class:`set` or its
subtype.
.. versionchanged:: 2.6
@@ -158,7 +158,7 @@
error is encountered. Does not raise :exc:`KeyError` for missing keys. Raise a
:exc:`TypeError` if the *key* is unhashable. Unlike the Python :meth:`~set.discard`
method, this function does not automatically convert unhashable sets into
- temporary frozensets. Raise :exc:`PyExc_SystemError` if *set* is an not an
+ temporary frozensets. Raise :exc:`PyExc_SystemError` if *set* is not an
instance of :class:`set` or its subtype.
@@ -166,7 +166,7 @@
Return a new reference to an arbitrary object in the *set*, and removes the
object from the *set*. Return *NULL* on failure. Raise :exc:`KeyError` if the
- set is empty. Raise a :exc:`SystemError` if *set* is an not an instance of
+ set is empty. Raise a :exc:`SystemError` if *set* is not an instance of
:class:`set` or its subtype.