EncounterSlot.condition_map = relation(EncounterSlotCondition, backref='slot')
EncounterSlot.conditions = association_proxy('condition_map', 'condition')
EncounterSlot.condition_map = relation(EncounterSlotCondition, backref='slot')
EncounterSlot.conditions = association_proxy('condition_map', 'condition')