def _as_sql(self, connection):
        obj = self.values("pk")
        if obj._db is None or connection == connections[obj._db]:
            return obj.query.get_compiler(connection=connection).as_nested_sql()
        raise ValueError("Can't do subqueries with queries on different DBs.")

    # When used as part of a nested query, a queryset will never be an "always
    # empty" result.
Given a class object, return a fully-qualified name.  This
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/db/models/query.py/QuerySet._as_sql--crossover with--dataset/ETHPy150Open ipython/ipython-py3k/docs/sphinxext/inheritance_diagram.py/InheritanceGraph.class_name