Issue #26778: Fixed "a/an/and" typos in code comment and documentation.
diff --git a/Doc/tutorial/introduction.rst b/Doc/tutorial/introduction.rst
index 40c0201..a4fb70c 100644
--- a/Doc/tutorial/introduction.rst
+++ b/Doc/tutorial/introduction.rst
@@ -307,7 +307,7 @@
 indices, if both are within bounds.  For example, the length of ``word[1:3]`` is
 2.
 
-Attempting to use a index that is too large will result in an error::
+Attempting to use an index that is too large will result in an error::
 
    >>> word[42]  # the word only has 6 characters
    Traceback (most recent call last):