Problem reported upstream:
https://github.com/linsomniac/python-memcached/issues/176

---
 memcache.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/memcache.py b/memcache.py
index 05b6657..b935681 100644
--- a/memcache.py
+++ b/memcache.py
@@ -1300,8 +1300,8 @@ class Client(threading.local):
             key = key[1]
         if key is None:
             raise Client.MemcachedKeyNoneError("Key is None")
-        if key is '':
-            if key_extra_len is 0:
+        if key == '':
+            if key_extra_len == 0:
                 raise Client.MemcachedKeyNoneError("Key is empty")

             #  key is empty but there is some other component to key
--
2.26.2
