'Add a transition to this Lifecycle configuration.  This only adds
the rule to the local copy.  To install the new rule(s) on
the bucket, you need to pass this Lifecycle config object
to the configure_lifecycle method of the Bucket object.
:ivar days: The number of days until the object should be moved.
:ivar date: The date when the object should be moved.  Should be
in ISO 8601 format.
:ivar storage_class: The storage class to transition to.  Valid
values are GLACIER, STANDARD_IA.'

def add_transition(self, days=None, date=None, storage_class=None):

    transition = Transition(days, date, storage_class)
    self.append(transition)
