-- Mauvais code
local Obj = {
    method1 = function(self, arg1, arg2, ...)
        --code
    end,
    method1 = function(self, arg1, arg2, ...)
        --code
    end,
    method3 = function(self, arg1, arg2, ...)
        --code
    end
}
return obj

-- Bon code
local Obj = {}
function Obj:method1(arg1, arg2)
    --stuff
end
function Obj:method2(arg1, arg2)
    --stuff
end
function Obj:method3(arg1, arg2)
    --stuff
end

return obj