def __init__(self, source=None):
"""
Creates a new EventRef instance, copying from the source if present.
"""
SecondaryObject.__init__(self)
PrivacyBase.__init__(self, source)
NoteBase.__init__(self, source)
AttributeBase.__init__(self, source)
RefBase.__init__(self, source)
if source:
self.role = source.role
else:
self.role = EventRoleType()
