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