diff --git a/fetch.py b/fetch.py
index 32af3e2..fead0e5 100644
--- a/fetch.py
+++ b/fetch.py
@@ -610,9 +610,10 @@ def is_usable_proxy(proxy):
     """
     with _proxy_valid_cache_lock:
         if proxy in _proxy_valid_cache:
-            # Move to end (most recently used)
-            _proxy_valid_cache.move_to_end(proxy)
-            return _proxy_valid_cache[proxy]
+            # Move to end (most recently used) - Python 2 compatible
+            value = _proxy_valid_cache.pop(proxy)
+            _proxy_valid_cache[proxy] = value
+            return value
 
     result = _validate_proxy(proxy)