code: def test_split_frame_empty():
      sf = zb.split_frame()
  
      assert len(sf) == 0
      assert len(sf.past) == 0
      assert len(sf.future) == 0
  
      sf = zb.split_frame(past={"x": [1, 2, 3]})
      assert len(sf) == 3
      assert len(sf.past) == 3
      assert len(sf.future) == 0
  
      sf = zb.split_frame(future={"x": [1, 2, 3]})
      assert len(sf) == 3
      assert len(sf.past) == 0
      assert len(sf.future) == 3
  
file_path: gluonts/test/zebras/test_timeframe.py
imports: import pytest
  import numpy
  import gluonts.zebras
label_desc: Use image node_id 7 for calling a global function with example usage: test_split_frame_empty() without return types