Issue #26778: Fixed "a/an/and" typos in code comment and documentation.
diff --git a/Doc/tutorial/datastructures.rst b/Doc/tutorial/datastructures.rst
index 48faa9c..0e5891a 100644
--- a/Doc/tutorial/datastructures.rst
+++ b/Doc/tutorial/datastructures.rst
@@ -452,7 +452,7 @@
 
 Though tuples may seem similar to lists, they are often used in different
 situations and for different purposes.
-Tuples are :term:`immutable`, and usually contain an heterogeneous sequence of
+Tuples are :term:`immutable`, and usually contain a heterogeneous sequence of
 elements that are accessed via unpacking (see later in this section) or indexing
 (or even by attribute in the case of :func:`namedtuples <collections.namedtuple>`).
 Lists are :term:`mutable`, and their elements are usually homogeneous and are
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):