Healing Item for Knight

local t = {
    storage = 41902
}

function onUse(cid, item, fromPosition, itemEx, toPosition)
    if not isKnight(cid) then
        doPlayerSendCancel(cid, 'Sorry, you cannot use this object.')
        return false
    end
    if getPlayerStorageValue(cid, t.storage) > 0 then
        doPlayerSendCancel(cid, 'You cannot use this during the event.')
        return false
    end

    local maxHealth = getCreatureMaxHealth(cid)
    local formula = ((maxHealth / 100) * math.random(30, 50))
    doCreatureAddHealth(cid, formula)
    doSendMagicEffect(getThingPos(cid), CONST_ME_MAGIC)
    return true
end