[NTG-context] letter module: File ended while scanning use of \buff_gobble

Hi, How could I embed \startletter/\stopletter in a macro please? This does not work: --8<---------------cut here---------------start------------->8--- \usemodule[letter] \def\myStartLetter{\startletter} \def\myStopLetter{\stopletter} \myStartLetter \input tufte \myStopLetter --8<---------------cut here---------------end--------------->8--- TIA for any hints, -- Peter