Sadly, dateutil is not actually part of the standard lib.

Thus, using the XEP-0082 and XEP-0202 introduces a dependency
on the dateutil package (installable using pip install python-dateutil).

Maybe we'll be able to rework how these plugins work to avoid
needing dateutil, but for now this will have to do.

sleekxmpp/plugins/xep_0202/stanza.py

@@ -6,12 +6,18 @@
     See the file LICENSE for copying permission.
 """
 
+import logging
 import datetime as dt
-from dateutil.tz import tzoffset, tzutc
 
 from sleekxmpp.xmlstream import ElementBase
 from sleekxmpp.plugins import xep_0082
 
+try:
+    from dateutil.tz import tzutc
+except:
+    log = logging.getLogger(__name__)
+    log.warning("XEP-0202 plugin requies dateutil package")
+
 
 class EntityTime(ElementBase):