update_or_create.py

class UpdateOrCreateMixin(object):
    """Mixin-Class for models.Manager subclasses.

    Provide the update_or_create method from Django 1.7 in earlier
    Djangos.

    """
    
    def update_or_create(self, defaults=None, **kwargs):
        """A convenience method for updating an object with the given kwargs,
        creating a new one if necessary. The defaults is a dictionary
        of (field, value) pairs used to update the object.

        Returns a tuple of (object, created), where object is the
        created or updated object and created is a boolean specifying
        whether a new object was created.

        The update_or_create method tries to fetch an object from
        database based on the given kwargs. If a match is found, it
        updates the fields passed in the defaults dictionary.

        """
        if defaults is None:
            defaults = {}
        key, created = SigningKey.objects.get_or_create(
            defaults=defaults,
            **kwargs
        )
        if not created:
            for attrib, value in defaults.items():
                setattr(key, attrib, value)
            key.save()
        return key, created