def __init__(self, name=None, description=None, start=None, end=None, location=None,
speaker=None, lists=None, master_list=None, id=None):
if getattr(start, "tzinfo", None) is None:
raise ValueError()
if getattr(end, "tzinfo", None) is None:
raise ValueError()
start, end = convert_to_utc(start, end)
self.name = name
self.description = description
self.start = start
self.end = end
self.location = location
self.speaker = speaker
if master_list not in lists:
raise ValueError("Master list must be in lists")
self.lists = lists
self.master_list = master_list
self.id = id
