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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 update_team(self, slug):
 """ Trigger an update and cache invalidation for the team identified by the given `slug`. Returns `True` on success, `False` otherwise. :param slug: The GitHub 'slug' that identifies the team in URLs """

        if slug not in self._teamobjects:
            # This case is checked and handled further up, but better be safe
            # than sorry.
            return False # pragma: no cover
        return self._teamobjects[slug].update()