code: def test_read_lightningignore_excludes_empty_lines(tmpdir):
      """_read_lightningignore() excludes empty lines."""
      test_path = tmpdir.join(".lightningignore")
      gitignore = """
  
      foo
  
      bar
  
  
  
      """
      test_path.write(gitignore)
  
      # results exclude all empty lines
      result = _read_lightningignore(test_path)
      assert len(result) == 2
  
imports: import os
  from lightning.app.source_code.copytree import _copytree, _read_lightningignore
label_desc: Use image node_id 2 for calling a global function with example usage: test_read_lightningignore_excludes_empty_lines(tmpdir) without return types