Added IDateTime interface

lib/python/DateTime/DateTime.py

@@ -19,6 +19,9 @@ import re, math,  DateTimeZone
 from time import time, gmtime, localtime
 from time import daylight, timezone, altzone, strftime
 from datetime import datetime
+from interfaces import IDateTime
+from interfaces import DateTimeError, SyntaxError, DateError, TimeError
+from zope.interface import implements
 
 default_datefmt = None
 
@@ -40,19 +43,6 @@ try:
 except:
     tzname=('UNKNOWN','UNKNOWN')
 
-class DateTimeError( Exception ):
-    pass
-
-class SyntaxError( DateTimeError ):
-    pass
-
-class DateError( DateTimeError ):
-    pass
-
-class TimeError( DateTimeError ):
-    pass
-
-
 # To control rounding errors, we round system time to the nearest
 # millisecond.  Then delicate calculations can rely on that the
 # maximum precision that needs to be preserved is known.
@@ -492,6 +482,8 @@ class DateTime:
         and numeric operations return a new DateTime object rather than
         modify the current object."""
 
+    implements(IDateTime)
+
     # For security machinery:
     __roles__=None
     __allow_access_to_unprotected_subobjects__=1