Why is this function going off when it's not being called?

function FindPlr(a, plr)
    local a = false
    for i,v in pairs(game.Players:GetPlayers()) do
        if string.find(string.lower(string.sub(v.Name,1,string.len(plr))),string.lower(plr),1,false) and plr ~= "" then
            a = v.Name
        end
        end
    return a
end
Functions.FindPlr.OnServerInvoke = FindPlr()

It's not being invoked though..........