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.

README

@@ -9,6 +9,9 @@ We try to keep requirements to a minimum, but we suggest that you install http:/
 If you do not install this library, you may need to specify the server/port for services that use SRV records (like GTalk).
 "sudo pip install dnspython" on a *nix system with pip installed.
 
+Two time related plugins (XEP-0082 and XEP-0202) also require the dateutil package, but that is not a hard requirement if you
+don't need those plugins. 
+
 SleekXMPP has several design goals/philosophies:
 - Low number of dependencies.
 - Every XEP as a plugin.

setup.py

@@ -54,11 +54,15 @@ packages     = [ 'sleekxmpp',
                  'sleekxmpp/plugins/xep_0059',
                  'sleekxmpp/plugins/xep_0060',
                  'sleekxmpp/plugins/xep_0060/stanza',
+                 'sleekxmpp/plugins/xep_0066',
                  'sleekxmpp/plugins/xep_0085',
                  'sleekxmpp/plugins/xep_0086',
                  'sleekxmpp/plugins/xep_0092',
                  'sleekxmpp/plugins/xep_0128',
-                 'sleekxmpp/plugins/xep_0199',
+                 'sleekxmpp/plugins/xep_0202',
+                 'sleekxmpp/plugins/xep_0203',
+                 'sleekxmpp/plugins/xep_0224',
+                 'sleekxmpp/plugins/xep_0249',
                  'sleekxmpp/features',
                  'sleekxmpp/features/feature_mechanisms',
                  'sleekxmpp/features/feature_mechanisms/stanza',

sleekxmpp/plugins/__init__.py

@@ -6,6 +6,20 @@
     See the file LICENSE for copying permission.
 """
 __all__ = ['xep_0004', 'xep_0009', 'xep_0012', 'xep_0030', 'xep_0033',
-           'xep_0045', 'xep_0050', 'xep_0060', 'xep_0066', 'xep_0082',
-           'xep_0085', 'xep_0086', 'xep_0092', 'xep_0128', 'xep_0199',
-           'xep_0202', 'xep_0203', 'xep_0224', 'xep_0249', 'gmail_notify']
+           'xep_0045', 'xep_0050', 'xep_0060', 'xep_0066', 'xep_0085',
+           'xep_0086', 'xep_0092', 'xep_0128', 'xep_0199', 'xep_0203',
+           'xep_0224', 'xep_0249', 'gmail_notify']
+
+# Some plugins may require external dependencies beyond what the
+# core SleekXMPP installation requires. Thus they should only by
+# imported automatically if those dependecies are met.
+
+HAVE_DATEUTIL = True
+try:
+    import dateutil
+except:
+    HAVE_DATEUTIL = False
+
+if HAVE_DATEUTIL:
+    __all__.append('xep_0082')
+    __all__.append('xep_0202')

sleekxmpp/plugins/xep_0082.py

@@ -6,11 +6,18 @@
     See the file LICENSE for copying permission.
 """
 
+import logging
 import datetime as dt
-from dateutil import parser
-from dateutil.tz import tzoffset, tzutc
+
 from sleekxmpp.plugins.base import base_plugin
 
+try:
+    from dateutil import parser
+    from dateutil.tz import tzoffset, tzutc
+except e:
+    log = logging.getLogger(__name__)
+    log.warning("XEP-0082 plugin requires dateutil")
+
 
 # =====================================================================
 # To make it easier for stanzas without direct access to plugin objects

sleekxmpp/plugins/xep_0202/__init__.py

@@ -6,6 +6,23 @@
     See the file LICENSE for copying permission.
 """
 
-from sleekxmpp.plugins.xep_0202 import stanza
-from sleekxmpp.plugins.xep_0202.stanza import EntityTime
-from sleekxmpp.plugins.xep_0202.time import xep_0202
+import logging
+import sleekxmpp
+
+
+log = logging.getLogger(__name__)
+
+
+HAVE_DATEUTIL = True
+try:
+    import dateutil
+except:
+    HAVE_DATEUTIL = False
+
+
+if HAVE_DATEUTIL:
+    from sleekxmpp.plugins.xep_0202 import stanza
+    from sleekxmpp.plugins.xep_0202.stanza import EntityTime
+    from sleekxmpp.plugins.xep_0202.time import xep_0202
+else:
+    log.warning("XEP-0202 requires the dateutil package")

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):