Codec is now derived from abc.ABC (#472)

* Codec is now derived from abc.ABC

* Add release note for `Codec(ABC)`

---------

Co-authored-by: jakirkham <[email protected]>

Author: madsbk

docs/release.rst

@@ -6,6 +6,16 @@ Release notes
     # to document your changes. On releases it will be
     # re-indented so that it does not show up in the notes.
 
+.. _release_0.12.1:
+
+0.12.1
+------
+
+Fix
+~~~
+
+* `Codec` is now derived from `abc.ABC`
+  By :user:`Mads R. B. Kristensen <madsbk>`, :issue:`472`.
 
 .. _release_0.12.0:
 

numcodecs/abc.py

@@ -29,10 +29,10 @@
 """
 
 
-from abc import abstractmethod
+from abc import ABC, abstractmethod
 
 
-class Codec:
+class Codec(ABC):
     """Codec abstract base class."""
 
     # override in sub-class