Update Set docstring [#1063].

diff --git a/dns/set.py b/dns/set.py
index 9081048a6a09304200cb9371d1867723641fb922..04826e2e6ef93069ad37ec0c44a1a0ae0d272567 100644 (file)
--- a/dns/set.py
+++ b/dns/set.py
@@ -21,10 +21,11 @@ import itertools
 class Set:
     """A simple set class.
 
-    This class was originally used to deal with sets being missing in
-    ancient versions of python, but dnspython will continue to use it
-    as these sets are based on lists and are thus indexable, and this
-    ability is widely used in dnspython applications.
+    This class was originally used to deal with python not having a set class, and
+    originally the class used lists in its implementation.  The ordered and indexable
+    nature of RRsets and Rdatasets is unfortunately widely used in dnspython
+    applications, so for backwards compatibility sets continue to be a custom class, now
+    based on an ordered dictionary.
     """
 
     __slots__ = ["items"]