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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 set_def_xml_acl(self, acl_str, key_name='', headers=None):
 """sets or changes a bucket's default object"""

        return self.set_xml_acl(acl_str, key_name, headers, 
                                query_args=DEF_OBJ_ACL)