old_contents: # coding: utf-8
  
  y1 = vector((1), (3))
  y2 = vector((1,1), (3,3))
  y3 = vector((1,1,1), (3,3,3))
  
new_contents: # coding: utf-8
  
  y1 = vector(1, 3)
  y2 = vector((1,1), (3,3))
  y3 = vector((1,1,1), (3,3,3))
  
subject: update ex vectors