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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 get_attachments_ids(self, ticket_id):
 """ Get IDs of attachments for given ticket. :param ticket_id: ID of ticket :returns: List of IDs (type int) of attachments belonging to given ticket. Returns None if ticket does not exist. """

        attachments = self.get_attachments(ticket_id)
        return [int(at[0]) for at in attachments] if attachments else attachments