get extra field value in Django's many-to-many relationship - django

Question

In Django's many-to-many relationships extra fields, we can add extra fields, as the code below (from https://docs.djangoproject.com/en/dev/topics/db/models/#intermediary-manytomany), my question is how could I get the extra field easily, is it possible to not query on the intermediary table directly? the exactly example is:
>>> ringo = Person.objects.create(name="Ringo Starr")
>>> paul = Person.objects.create(name="Paul McCartney")
>>> beatles = Group.objects.create(name="The Beatles")
>>> m1 = Membership(person=ringo, group=beatles,
... date_joined=date(1962, 8, 16),
... invite_reason="Needed a new drummer.")
>>> m1.save()
>>> beatles.members.all()
[<Person: Ringo Starr>]
>>> p = beatles.members.all()[0]
>>> p
[<Person: Ringo Starr>]
I want to get the date_joined value of p, I know it can be done by
>>> Membership.objects.get(person=p, group=beatles).date_joined
datetime.date(1962, 8, 16)
but is it possible to get it simply just like:
>>> p.xxx(*args)
=============== models.py ================
from django.db import models
class Person(models.Model):
name = models.CharField(max_length=128)
def __str__(self): # __unicode__ on Python 2
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership')
def __str__(self): # __unicode__ on Python 2
return self.name
class Membership(models.Model):
person = models.ForeignKey(Person)
group = models.ForeignKey(Group)
date_joined = models.DateField()
invite_reason = models.CharField(max_length=64)

Answer 1

From the documentation page you link to:
Another way to access the same information is by querying the many-to-many reverse relationship from a Person object:
>>> ringos_membership = ringo.membership_set.get(group=beatles)
>>> ringos_membership.date_joined
datetime.date(1962, 8, 16)
>>> ringos_membership.invite_reason
'Needed a new drummer.'