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.

2 files changed, 3 insertions, 3 deletions

diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 45c31a550e..44116d8864 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -75,7 +75,7 @@ PyDoc_STRVAR(module_doc,
 "Another IOBase subclass, TextIOBase, deals with the encoding and decoding\n"
 "of streams into text. TextIOWrapper, which extends it, is a buffered text\n"
 "interface to a buffered raw stream (`BufferedIOBase`). Finally, StringIO\n"
-"is a in-memory stream for text.\n"
+"is an in-memory stream for text.\n"
 "\n"
 "Argument names are not part of the specification, and only the arguments\n"
 "of open() are intended to be used as keyword arguments.\n"
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index b419275a80..0c1b13ec29 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -931,8 +931,8 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
         if (self->encoding == NULL) {
           catch_ImportError:
             /*
-             Importing locale can raise a ImportError because of
-             _functools, and locale.getpreferredencoding can raise a
+             Importing locale can raise an ImportError because of
+             _functools, and locale.getpreferredencoding can raise an
              ImportError if _locale is not available.  These will happen
              during module building.
             */