def quote_name_unless_alias(self, name):
        if name in self.quote_cache:
            return self.quote_cache[name]
        if ((name in self.query.alias_map and name not in self.query.table_map) or
                name in self.query.extra_select):
            self.quote_cache[name] = name
            return name
        r = self.connection.ops.quote_name(name)
        self.quote_cache[name] = r
        return r
Given a linkage matrix Z, return the cut tree.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/django/db/models/sql/compiler.py/SQLCompiler.quote_name_unless_alias--crossover with--dataset/ETHPy150Open scipy/scipy/scipy/cluster/hierarchy.py/cut_tree