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
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<tr><td><span title='2021-02-01 14:18:38 -0500'>2021-02-01</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=75b775e81b5a81a59656eeba8811b42f45d503da'>Merge branch 'staging'</a></td><td>Leo Famulari</td></tr>
<tr><td><span title='2021-01-28 12:57:26 +0100'>2021-01-28</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=6c0679215f4ffa534c1eb2e8c8a6e043a0c993fe'>services: postgresql: Add socket directory support.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/databases.scm (postgresql-config-file-socket-directory): New
procedure.
(&lt;postgresql-config-file&gt;)[socket-directory]: New field.
(postgresql-config-file-compiler): Honor it.
(postgresql-activation): Create the socket directory if needed.
* doc/guix.texi (Database Services): Document it.
* gnu/tests/guix.scm (%guix-data-service-os): Adapt it.
* gnu/tests/monitoring.scm (%zabbix-os): Ditto.
* gnu/tests/web.scm (patchwork-os): Ditto.

Signed-off-by: Mathieu Othacehe &lt;othacehe@gnu.org&gt;
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2021-01-04 18:07:53 -0500'>2021-01-04</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=48d8d92c51f64256bba2bdbb2a1027a5fab71a3d'>tests: monitoring: Use the latest postgresql for testing Zabbix.</a><span class='msg-avail'>...<span class='msg-tooltip'>This avoids a package collision while building the operating-system profile.

* gnu/tests/monitoring.scm (%zabbix-os): Use POSTGRESQL instead of
POSTGRESQL-10.
</span></span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2020-10-20 22:39:43 +0100'>2020-10-20</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=bdcf4d88d58798eca7811c8b1fbd4638168d05c3'>services: databases: Don't specify a default postgresql version.</a><span class='msg-avail'>...<span class='msg-tooltip'>Currently, if the postgresql package major version changes, this is going to
break the service upon upgrade, because PostgreSQL will reject the data files
from the differing major version of the service.

Because it's important to either keep running a particular major version, or
intentionally upgrade, I think the configuration would be better with no
default. I think this is also going to be helpful when trying to assist users
upgrading PostgreSQL.

* gnu/services/databases.scm (&lt;postgresql-configuration&gt;): Remove default for
postgresql.
(postgresql-service-type): Remove the default value.
* gnu/tests/databases.scm (%postgresql-os): Update accordingly.
* gnu/tests/guix.scm (%guix-data-service-os): Update accordingly.
* gnu/tests/monitoring.scm (%zabbix-os): Update accordingly.
* gnu/tests/web.scm (patchwork-os): Update accordingly.
* doc/guix.texi (PostgreSQL): Update accordingly.
</span></span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2020-10-20 22:39:42 +0100'>2020-10-20</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=dd2e6e31edff2d83c8820bb10e588c06495dc122'>tests: monitoring: Use (service postgresql-service-type).</a><span class='msg-avail'>...<span class='msg-tooltip'>As I'm looking at removing the procedure, in favour of always using the
service type.

* gnu/tests/monitoring.scm (%zabbix-os): Use (service postgresql-service-type)
rather than (postgresql-service).
</span></span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2020-07-15 22:15:50 +0300'>2020-07-15</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=37fea3c30a79d2c401dd64b446a0fbfe4a14b966'>tests: zabbix: Fix typo in comment.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests/monitoring.scm (run-zabbix-server-test)[test]: Fix typo in
comment.
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-03-09 23:46:36 +0100'>2020-03-09</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=7e5f016cdbca09b6ee2af71e495002e7686ef6f7'>tests: zabbix: Set 'PATH' before running the scripts.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 8b9cad01e9619f53dc5a65892ca6a09ca5de3447.

* gnu/tests/monitoring.scm (run-zabbix-server-test)[test]: Set 'PATH' in
MARIONETTE.
</span></span></td><td>Ludovic Courtès</td></tr>