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, 1 insertions, 1 deletions

diff --git a/Doc/tutorial/errors.rst b/Doc/tutorial/errors.rst
index d048ae9..351ee52 100644
--- a/Doc/tutorial/errors.rst
+++ b/Doc/tutorial/errors.rst
@@ -336,7 +336,7 @@ example::
 A *finally clause* is always executed before leaving the :keyword:`try`
 statement, whether an exception has occurred or not. When an exception has
 occurred in the :keyword:`try` clause and has not been handled by an
-:keyword:`except` clause (or it has occurred in a :keyword:`except` or
+:keyword:`except` clause (or it has occurred in an :keyword:`except` or
 :keyword:`else` clause), it is re-raised after the :keyword:`finally` clause has
 been executed.  The :keyword:`finally` clause is also executed "on the way out"
 when any other clause of the :keyword:`try` statement is left via a