How does yade import models externally

Hello all:
I tried importing the Rhino-generated gts model into yade, but it ran incorrectly. Then use Rhino to export stl file, after conversion into gts file can be run

from yade import pack
import gts, os.path, locale

surf=gts.read(open('1027.gts'))

if surf.is_closed():
 pred=pack.inGtsSurface(surf)
 aabb=pred.aabb()
 dim0=aabb[1][0]-aabb[0][0]; radius=dim0/70. # get some characteristic dimension, use it for radius
 O.bodies.appendClumped(pack.regularHexa(pred,radius=radius,gap=radius/4.))
 surf.translate(0,-(aabb[1][1]-aabb[0][1])/2.0,-(aabb[1][2]-aabb[0][2])) # move surface down so that facets are underneath the falling spheres
O.bodies.append(pack.gtsSurface2Facets(surf,wire=True))

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()],label='collider'),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()],
  [Ip2_FrictMat_FrictMat_FrictPhys()],
  [Law2_ScGeom_FrictPhys_CundallStrack()],
 ),
 NewtonIntegrator(damping=.1,gravity=[0,0,-500.0]),
 PyRunner(iterPeriod=1000,command='timing.stats(); O.pause();'),
 PyRunner(iterPeriod=10,command='addPlotData()')
]
O.dt=.7*PWaveTimeStep()
O.saveTmp()
O.timingEnabled=True
O.trackEnergy=True
from yade import plot
plot.plots={'i':('total',O.energy.keys,)}
def addPlotData(): plot.addData(i=O.iter,total=O.energy.total(),**O.energy)
plot.plot(subPlots=False)

from yade import timing
from yade import qt
qt.View()

Traceback (most recent call last):
  File "/usr/bin/yade", line 336, in runScript
    execfile(script,globals())
  File "/usr/lib/python3/dist-packages/past/builtins/misc.py", line 87, in execfile
    exec_(code, myglobals, mylocals)
  File "HT.py", line 8, in <module>
    surf=gts.read(open('1027.gts'))
RuntimeError: expecting a number (z coordinate)

Thank you in advance!