core/util: fix Mapping moving around in stdlib `collections`

sx/core/util.py

@@ -1,7 +1,7 @@
 import os
 import inspect
 import ast
-import collections
+import collections.abc
 from typing import BinaryIO, Generator, Callable, Optional as O, Union as U, Tuple, Mapping, Any, cast
 from contextlib import contextmanager
 
@@ -48,7 +48,7 @@ def format_bytes(bs: bytes, cutoff=256) -> str:
 
 def format_value(value: Any, formatter: Callable[[Any], str], indentation: int = 0) -> str:
     """ Format containers to use the given formatter function instead of always repr(). """
-    if isinstance(value, (dict, collections.Mapping)):
+    if isinstance(value, (dict, collections.abc.Mapping)):
         if value:
             fmt = '{{\n{}\n}}'
             values = [indent(',\n'.join('{}: {}'.format(