fields plot 3d

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In sagemath CLOUD i can't plot vector fields in 3d :

x,y,z = var ('x y z')
plot_vector_field3d((x*cos(z),-y*cos(z),sin(z)), (x,0,pi), (y,0,pi), (z,0,pi),center_arrows=True,aspect_ratio=(1,2,1))

error reported:
Error in lines 2-2 Traceback (most recent call last): File "/mnt/home/WmaalNmo/.sagemathcloud/sage_server.py", line 668, in execute exec compile(block+'\n', '', 'single') in namespace, locals File "", line 1, in <module> File "/mnt/home/WmaalNmo/.sagemathcloud/sage_salvus.py", line 2723, in displayhook show(obj) File "/mnt/home/WmaalNmo/.sagemathcloud/sage_salvus.py", line 2082, in show graphics.show_3d_plot_using_threejs(obj, **kwds) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 119, in show_3d_plot_using_threejs t.add(g, **kwds) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 81, in add self._call('add_3dgraphics_obj(obj)', obj={'obj':graphics3d_to_jsonable(graphics3d), 'wireframe':jsonable(kwds.get('wireframe'))}) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 387, in graphics3d_to_jsonable handler(p)(p) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 359, in convert_combination handler(x)(x) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 365, in convert_inner handler(p.all[0])(p) File "/mnt/home/WmaalNmo/.sagemathcloud/graphics.py", line 346, in convert_line "points" : p.points, AttributeError: 'TransformGroup' object has no attribute 'points'

thank you for your help.

Félix.