State Pattern - Django models

I'm currently trying to implement the state pattern in Django. Take these models for example:

class Restaurant(models.Model):
    name = models.CharField()
    # other fields here ...


class State(models.Model):
    pass

class StateOpen(State):
    def toggle_open_closed():
        pass

class StateClosed(State):
    def toggle_open_closed():
        pass

now how can I make my restaurant have a state, and this state can either be a StateOpen or StateClosed?

Edit: Ideally I would want to be able to do something like that:

r = Restaurant(name='whatever')
r.state.doSomething()

# doSomething() being a function that each state child class has,
# but implemented differently