class ToTo(EntityType):

    permissions = {

        'read': ('managers',),

        'add': ('managers',),

        'update': ('managers',),

        'delete': ('managers',),

        }

    toto = SubjectRelation('TuTu')

class TuTu(EntityType):

    permissions = {

        'read': ('managers',),

        'add': ('managers',),

        'update': ('managers',),

        'delete': ('managers',),

        }

class toto(RelationType):

    permissions = {

        'read': ('managers', ),

        'add': ('managers', ERQLExpression('S bla Y'),),

        'delete': ('managers',),

        }