Fixed undefined variables in collate function
Fixed undefined variables in collate function

vascotenner/holoviews,ioam/holoviews,basnijholt/holoviews,basnijholt/holoviews,ioam/holoviews,basnijholt/holoviews,vascotenner/holoviews,ioam/holoviews,vascotenner/holoviews