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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 has_var_groups(self):
        '''Returns a set of the variant group ids that this cluster has'''
        ids = set()
        for d in self.data:
            if self._has_known_variant(d) != 'no' and d['var_group'] != '.':
                ids.add(d['var_group'])
        return ids