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