get current io input

[buttercheetah 0]

i am currently trying to make a small script that temporarily changes the io input to a file and then back to the previews input. i have tried searching for solutions and all i found was this from lua.org

    local temp = io.input()   -- save current file
    io.input("newinput")      -- open a new current file
    ...                       -- do something with new input
    io.input():close()        -- close current file
    io.input(temp)            -- restore previous current file

however when i attempt this i get this error Bad Argument #1 (string or file expected, got table): i am relatively new to lua so any help would be outstanding

Thanks.