def __init__(self, inequality, timespan=None, offset=None):
TimeRelation.__init__(self, inequality)
self._timespan = timespan
self._offset = offset
def __init__(self, inequality, timespan_1=None, timespan_2=None):
TimeRelation.__init__(self, inequality)
self._timespan_1 = timespan_1
self._timespan_2 = timespan_2