Issue #25523: Correct "a" article to "an" article

This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
or edited some other way to fix the grammar.

1 files changed, 2 insertions, 2 deletions

diff --git a/Doc/library/concurrent.futures.rst b/Doc/library/concurrent.futures.rst
index cc8b335b8f..e63e741b2e 100644
--- a/Doc/library/concurrent.futures.rst
+++ b/Doc/library/concurrent.futures.rst
@@ -81,7 +81,7 @@ Executor Objects
 ThreadPoolExecutor
 ------------------
 
-:class:`ThreadPoolExecutor` is a :class:`Executor` subclass that uses a pool of
+:class:`ThreadPoolExecutor` is an :class:`Executor` subclass that uses a pool of
 threads to execute calls asynchronously.
 
 Deadlocks can occur when the callable associated with a :class:`Future` waits on
@@ -285,7 +285,7 @@ The :class:`Future` class encapsulates the asynchronous execution of a callable.
 
        Added callables are called in the order that they were added and are
        always called in a thread belonging to the process that added them.  If
-       the callable raises a :exc:`Exception` subclass, it will be logged and
+       the callable raises an :exc:`Exception` subclass, it will be logged and
        ignored.  If the callable raises a :exc:`BaseException` subclass, the
        behavior is undefined.