bpo-26103: Fix inspect.isdatadescriptor() and a data descriptor definition. (GH-1959)
Look for '__set__' or '__delete__'.
diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index 5e85a9a..6e4aa3e 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -58,7 +58,7 @@
considered a descriptor and can override default behavior upon being looked up
as an attribute.
-If an object defines both :meth:`__get__` and :meth:`__set__`, it is considered
+If an object defines :meth:`__set__` or :meth:`__delete__`, it is considered
a data descriptor. Descriptors that only define :meth:`__get__` are called
non-data descriptors (they are typically used for methods but other uses are
possible).