Avoid DeprecationWarning

Using or importing the ABCs from 'collections' instead of from
'collections.abc' is deprecated, and in 3.8 it will stop working.

Preserves Python 2 compatibility.

Author: hroncok

socks.py

@@ -55,7 +55,10 @@
 """
 
 from base64 import b64encode
-from collections import Callable
+try:
+    from collections.abc import Callable
+except ImportError:
+    from collections import Callable
 from errno import EOPNOTSUPP, EINVAL, EAGAIN
 import functools
 from io import BytesIO