27     lookup_field = 'ext_id'

    27     lookup_field = 'ext_id'

    28 

    28 

    29     serializers = {

    29     serializers = {

    30         'list': ListSessionSerializer,

    30         'list': ListSessionSerializer,

    31         'retrieve':  DetailSessionSerializer,

    31         'retrieve':  DetailSessionSerializer,

    32         'create':  CreateSessionSerializer,

    33         'create':  CreateSessionSerializer,

    33     }

    34     }

    34 

    35 

    35     permission_classes = (SessionPermission,)

    36     permission_classes = (SessionPermission,)

    36 

    37