Gets any assets associated with this activity.

        return: (osid.repository.AssetList) - list of assets
        raise:  IllegalState - is_asset_based_activity() is false
        raise:  OperationFailed - unable to complete request
        compliance: mandatory - This method must be implemented.

def get_assets(self):
        """Gets any assets associated with this activity.

        return: (osid.repository.AssetList) - list of assets
        raise:  IllegalState - is_asset_based_activity() is false
        raise:  OperationFailed - unable to complete request
        compliance: mandatory - This method must be implemented.

        """
        # This includes a kludge to get the objectiveBankId directly from
        # this Activity's Objective's private _my_map :o
        from ..repository.objects import AssetList
        if not self.is_asset_based_activity():
            raise IllegalState()
        url_str = (self._base_url + '/objectivebanks/' +
                   self.get_objective()._my_map['objectiveBankId'] +
                   '/assets/bulk?id=' + '&id='.join(self._my_map['assetIds']))
        return AssetList(self._load_json(url_str))