Post #1276: 
Leafar:
Ok, but it is possible using a regular hotkey like the spacebar for example???
Yes, but not the spacebar. Spacebar is used to confirm 3d manipulator tool (translate, rotate, scale).
Use Sticky Key with this code:
On Press:
bpy.context.space_data.show_manipulator = True
On Release:
bpy.context.space_data.show_manipulator = False