code: def test_batch_split_frame():
      sf0 = zb.time_frame(
          {"x": [1, 2, 3]},
          start="2020",
          freq="D",
          metadata={"item_id": 0},
      ).split(1, past_length=4, future_length=3)
      sf1 = zb.time_frame({"x": [4, 5, 6]}).split(
          1, past_length=4, future_length=3
      )
  
      batched = zb.batch([sf0, sf1])
  
      assert len(batched) == 7
      assert batched.batch_size == 2
  
      sf0x, sf1x = batched.items()
  
imports: import pytest
  import numpy
  import gluonts.zebras
label_desc: Use image node_id 3 for calling a global function with example usage: test_batch_split_frame() without return types