Subtract gr_sub_xx from gnuradio import gr gr.sub_$(type.fcn)($vlen) IO Type type enum Complex complex fcn:cc Float float fcn:ff Int int fcn:ii Short short fcn:ss Vec Length vlen 1 int Num Inputs num_inputs 2 int $vlen > 0 $num_inputs >= 2 in $type $vlen $num_inputs out $type $vlen