slot0 = class("ItemUsage")
slot0.UNDEFINED = "usage_undefined"
slot0.BOOK = "usage_book"
slot0.DROP = "usage_drop"
slot0.FOOD = "usage_food"
slot0.ADD_EXP = "usage_add_exp"
slot0.ADD_RESOURCE = "usage_add_resource"
slot0.ADD_SHIP = "usage_add_ship"
slot0.DORM_LV_UP = "usage_dorm_lv_up"
slot0.DROP_APPOINTED = "usage_drop_appointed"
slot0.SOS = "usage_sos"

return slot0