code: def test_batch_time_series():
      ts0 = zb.time_series(
          [1, 2, 3],
          start="2020",
          freq="D",
          metadata={"item_id": 0},
          name="x",
      )
      ts1 = zb.time_series([4, 5, 6])
  
      batched = zb.batch([ts0, ts1])
  
      assert len(batched) == 3
      assert batched.batch_size == 2
  
      ts0x, ts1x = batched.items()
  
      np.testing.assert_array_equal(ts0, ts0x)
      assert ts0.metadata == ts0x.metadata
      assert ts0.tdim == ts0x.tdim
      assert ts0.name == ts0x.name
      assert ts0._pad == ts0x._pad
  
      np.testing.assert_array_equal(ts1, ts1x)
      assert ts1.metadata == ts1x.metadata
      assert ts1.tdim == ts1x.tdim
      assert ts1.name == ts1x.name
      assert ts1._pad == ts1x._pad
  
imports: import pytest
  import numpy
  import gluonts.zebras
label_desc: Use image node_id 1 for calling a global function with example usage: test_batch_time_series() without return types