Issue #26778: Fixed "a/an/and" typos in code comment and documentation.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 2584560..523620e 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1525,9 +1525,9 @@
 
            'x' or 'x:'  create a tarfile exclusively without compression, raise
                         an exception if the file is already created
-           'x:gz'       create an gzip compressed tarfile, raise an exception
+           'x:gz'       create a gzip compressed tarfile, raise an exception
                         if the file is already created
-           'x:bz2'      create an bzip2 compressed tarfile, raise an exception
+           'x:bz2'      create a bzip2 compressed tarfile, raise an exception
                         if the file is already created
            'x:xz'       create an lzma compressed tarfile, raise an exception
                         if the file is already created