reduce player name size

[Sashapty]

Hello, I'm using the addon from this post https://www.wowinterface.com/forums/...ad.php?t=59179
it still works, but I started getting LUA errors. Please help me to fix this/
the addon itself:

local function SizeName(self) 
    local font, size = self.name:GetFont() 
    self.name:SetFont(font, size-1) 
end 
SizeName(PlayerFrame) 
SizeName(TargetFrame) 
SizeName(TargetFrameToT)
SizeName(FocusFrame)
for i=1, 4 do 
    SizeName(_G["PartyMemberFrame"..i]) 
end

and LUA error that I get:

Message: Interface/AddOns/FlickNameSize/core.lua:2: attempt to index local 'self' (a nil value)
Time: Sat Sep 16 08:36:27 2023
Count: 1
Stack: Interface/AddOns/FlickNameSize/core.lua:2: attempt to index local 'self' (a nil value)
[string "@Interface/AddOns/FlickNameSize/core.lua"]:2: in function `SizeName'
[string "@Interface/AddOns/FlickNameSize/core.lua"]:10: in main chunk

Locals: self = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to index local 'self' (a nil value)"