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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def parse_dota_um(self, event):
 """ The chat messages that arrive when certain events occur. The most useful ones are CHAT_MESSAGE_RUNE_PICKUP, CHAT_MESSAGE_RUNE_BOTTLE, CHAT_MESSAGE_GLYPH_USED, CHAT_MESSAGE_TOWER_KILL """

        if event.type == dota_usermessages_pb2.CHAT_MESSAGE_AEGIS:
            self.aegis.append((self.tick, event.playerid_1))