code: def test_black():
      runner = CliRunner()
      result = runner.invoke(black.main, [str(code_root), "--check"])
      assert result.exit_code == 0, result.output
  
imports: import black
  from click.testing import CliRunner
  from pathlib import Path
  import pytest
  import sys
label_desc: Use image node_id 1 for calling a global function with example usage: test_black() without return types