Can't see any indication in the 3D view , when changing mesh properties from python c

Im using blender 2.75 in windows , i try to change the default cube model simple property data.edge[0].bevel_weight to 1.0
but i don’t see any bevel change in the cube model in the 3d View
in the python console i do :

>>> cube  = bpy.context.active_object
>>> cube.data.edges[0]
bpy.data.meshes['Cube'].edges[0]
>>> cube.data.edges[0].bevel_weight
0.0
>>> cube.data.edges[1].bevel_weight = 1.0
>>> cube.data.edges[1].bevel_weight
1.0

looks like in the script it is working but why i dont see any thing in the 3DView?

Hi, I’m not experienced with bpy but: http://www.pasteall.org/blend/38814 (run script)