Proboolean “Imprint” option doesn’t work.

P1 is a Epoly converted from plan(), and P2 is an extruded spline, which intersect with P1, I want to “cut” P1 using P2, instead of manually do it.
proboolean.setoperandA $p1
proboolean.setboolop $p1 1
proboolean.setimprint $p1 true--not work out. Always returns “false” not “ok”.
proboolean.setoperandB $p1 $p2 2 1--not work out. The result Boolean compound doesn’t show the cutting line.
Anything wrong?