add make_primitive() support for HELIX
@@ -164,6 +164,7 @@ _PRIMITIVE_CLASSES = {
"ARC": CurvePrimitive,
"CIRCLE": CurvePrimitive,
"ELLIPSE": CurvePrimitive,
+ "HELIX": CurvePrimitive,
"LINE": LinePrimitive,
"LWPOLYLINE": LwPolylinePrimitive,
"POINT": PointPrimitive,
