code: def test_blockpartition_short_sequence():
      with pytest.raises(ValueError):
          blockpartition.solve([], partitions=1)
      with pytest.raises(ValueError):
          blockpartition.solve([42], partitions=2)
  
imports: import time
  import pytest
  import torch
  from torch import nn
  from fairscale.nn.pipe.balance import balance_by_size, balance_by_time, blockpartition
  from fairscale.nn.pipe.balance.profile import layerwise_sandbox
label_desc: Use image node_id 4 for calling a global function with example usage: test_blockpartition_short_sequence() without return types