code: def test_check_instances_list_formatting():
      """[Utils] check_instances: test formatting of list."""
  
      instances = [
          OLS(),
          ("ols", OLS()),
          ("ols", OLS()),
          ["list", OLS()],
      ]
      formatted = _check_instances(instances)
  
      strings = []
      for i in formatted:
          assert isinstance(i, tuple)
          assert isinstance(i[0], str)
          assert isinstance(i[1], OLS)
          assert i[0] not in strings
          strings.append(i[0])
  
file_path: mlens/mlens/utils/tests/test_formatting.py
imports: from mlens.utils.dummy import OLS
  from mlens.utils.formatting import _check_format, _assert_format, _format_instances, _check_instances
label_desc: Use image node_id 13 for calling a global function with example usage: test_check_instances_list_formatting() without return types