Frame error from Artifact

[Uitat]

1x FrameXML\MainMenuBar.lua:125: Usage: local cost = C_ArtifactUI.GetCostForPointAtRank(rank, tier)
[C]: in function `GetCostForPointAtRank'
FrameXML\MainMenuBar.lua:125: in function `MainMenuBar_GetNumArtifactTraitsPurchasableFromXP'
_Deranjata\modules\xpbar\artxp.lua:34: in function <_Deranjata\modules\xpbar\artxp.lua:29>

Locals:
(*temporary) = 38
(*temporary) = nil

Here is the function in its entirety, im really struggling to figure out what is broken i can find no documentation that any of these were changed or discontinued

derArtifactBar:SetScript("OnEvent", function(self, event, ...)
    if not HasArtifactEquipped() then self:Hide() return end
    self:Show()
 
    local itemID, altItemID, name, icon, totalXP, pointsSpent = C_ArtifactUI.GetEquippedArtifactInfo()
    local numPoints, artifactXP, xpForNextPoint = MainMenuBar_GetNumArtifactTraitsPurchasableFromXP(pointsSpent, totalXP)
    self:SetMinMaxValues(0,xpForNextPoint)
    self:SetValue(artifactXP)
 
    self.Text:SetFormattedText("Artifact XP: %d / %d       +%d Points",artifactXP,xpForNextPoint,numPoints)
end)