input: Write a function to determine if it is possible to get a given list of 3-dimensional vectors sorted by the sum of their coordinates in ascending order by performing any number of right shift operations on the list. If it is possible return True else return False. If the given list is empty or contains vectors with the same sum then return True.
  assert sortable_vectors([Vector(1, 2, 3), Vector(5, 3, 2), Vector(4, 4, 4)])==True
  assert sortable_vectors([Vector(1, 2, 3), Vector(5, 3, 2), Vector(4, 4, 3)])==True
  assert sortable_vectors([Vector(1, 2, 3), Vector(5, 3, 2), Vector(4, 4, 5)])==False
  assert sortable_vectors([Vector(1, 2, 3), Vector(5, 3, 2), Vector(4, 4, 2)])==False
  assert sortable_vectors([])==True
output: def sortable_vectors(vectors):
      if not vectors:
          return True
      sums = [sum(v) for v in vectors]
      sorted_sums = sorted(sums)
      for _ in range(len(sums)):
          if sums == sorted_sums:
              return True
          sums = sums[1:] + sums[:1]
      return False