simdata: update MutableMapping location

It was moved to collections.abc

1 files changed, 2 insertions, 2 deletions

diff --git a/simdata.py b/simdata.py
index 6dfed8d..fd238ae 100644
--- a/simdata.py
+++ b/simdata.py
@@ -3,7 +3,7 @@ This module provides a wrapper around a Cactus simulation output, i.e. a directo
 """
 
 import os
-import collections
+from collections.abc import MutableMapping
 
 from . import datafile
 
@@ -74,7 +74,7 @@ class _RefinementLevel(object):
     def slice(self, iteration = -1, time = -1):
         return _RefinedSlice(self._sd, self, time, iteration)
 
-class _DataDir(collections.MutableMapping):
+class _DataDir(MutableMapping):
     _files = None
     _paths = None