[web2py] Get query from string

[toan75]

I have string, ex: "((person.id>0)&(person.car=car.id))", i like get
my query = (db.person.id>0) & (db.person.car==db.car.id),  same like
get_query function in appadmin controller?

def get_query(request):
        try:
                return eval_in_global_env(request.vars.query)
        except Exception:
                return None

Pls help me. Thanks.