Merge pull request #69 from hugovk/fix-deprecation

Fix ImportError in Python 3.9

Author: agoode

doc/index.rst

@@ -99,15 +99,15 @@ OpenSlide objects
    .. attribute:: properties
 
       Metadata about the slide, in the form of a
-      :class:`Mapping <collections.Mapping>` from OpenSlide property name to
+      :class:`~collections.abc.Mapping` from OpenSlide property name to
       property value.  Property values are always strings.  OpenSlide
       provides some :ref:`standard properties <Standard properties>`, plus
       additional properties that vary by slide format.
 
    .. attribute:: associated_images
 
       Images, such as label or macro images, which are associated with this
-      slide.  This is a :class:`Mapping <collections.Mapping>` from image
+      slide.  This is a :class:`~collections.abc.Mapping` from image
       name to RGBA :class:`Image <PIL.Image.Image>`.
 
       Unlike in the C interface, these images are not premultiplied.

openslide/__init__.py

@@ -23,9 +23,15 @@
 """
 
 from __future__ import division, print_function
-from collections import Mapping
 from PIL import Image
 
+try:
+    # Python 3.3+
+    from collections.abc import Mapping
+except ImportError:
+    # Python 2
+    from collections import Mapping
+
 from openslide import lowlevel
 
 # For the benefit of library users