When you need to create a record of a model and delete duplicates same time you can use this method.

get_first_or_create.py

def create_and_delete_others(cls, **kwargs):
    """
    1. Get first record of model cls from db with given kwargs.
    2. If found, update that record with update_params.
    2. If not found, create instance with create_params.
    3. If more than one found, delete others.
    """
    create_params = kwargs.pop('create_params', {})
    update_params = kwargs.pop('update_params', {})
    save_params = kwargs.pop('save_params', {})

    created = False
    try:
        instance = cls.objects.get(**kwargs)
    except cls.DoesNotExist:
        created = True
        instance = cls(**create_params)
    except cls.MultipleObjectsReturned:
        instance = cls.objects.filter(**kwargs)[0]

        # We're deleting redundant instances one by one to call delete
        # method inside klass.
        for _i in cls.objects.filter(**kwargs).exclude(instance.id):
            _i.delete()

    if update_params:
        for k, v in update_params.iteritems():
            setattr(instance, k, v)

    instance.save(**save_params)

    if created:
        logger.info('Created %s with: %s, called save with params: %s' \
            % (cls.__name__, create_params, save_params))
    else:
        logger.info('Found %s with: %s, called save with params: %s' % \
            (cls.__name__, kwargs, save_params))

    return created, instance