Added __slots__ to the trigger classes

3 files changed, 6 insertions, 0 deletions

diff --git a/apscheduler/triggers/cron/__init__.py b/apscheduler/triggers/cron/__init__.py
index c3dca9d..8df901e 100644
--- a/apscheduler/triggers/cron/__init__.py
+++ b/apscheduler/triggers/cron/__init__.py
@@ -40,6 +40,8 @@ class CronTrigger(BaseTrigger):
         'second': BaseField
     }
 
+    __slots__ = 'timezone', 'start_date', 'end_date', 'fields'
+
     def __init__(self, year=None, month=None, day=None, week=None, day_of_week=None, hour=None, minute=None,
                  second=None, start_date=None, end_date=None, timezone=None):
         if timezone:
diff --git a/apscheduler/triggers/date.py b/apscheduler/triggers/date.py
index b5b153f..237e6b4 100644
--- a/apscheduler/triggers/date.py
+++ b/apscheduler/triggers/date.py
@@ -14,6 +14,8 @@ class DateTrigger(BaseTrigger):
     :param datetime.tzinfo|str timezone: time zone for ``run_date`` if it doesn't have one already
     """
 
+    __slots__ = 'timezone', 'run_date'
+
     def __init__(self, run_date=None, timezone=None):
         timezone = astimezone(timezone) or get_localzone()
         self.run_date = convert_to_datetime(run_date or datetime.now(), timezone, 'run_date')
diff --git a/apscheduler/triggers/interval.py b/apscheduler/triggers/interval.py
index 0f7c836..025161a 100644
--- a/apscheduler/triggers/interval.py
+++ b/apscheduler/triggers/interval.py
@@ -22,6 +22,8 @@ class IntervalTrigger(BaseTrigger):
     :param datetime.tzinfo|str timezone: time zone to use for the date/time calculations
     """
 
+    __slots__ = 'timezone', 'start_date', 'end_date', 'interval'
+
     def __init__(self, weeks=0, days=0, hours=0, minutes=0, seconds=0, start_date=None, end_date=None, timezone=None):
         self.interval = timedelta(weeks=weeks, days=days, hours=hours, minutes=minutes, seconds=seconds)
         self.interval_length = timedelta_seconds(self.interval)