def METHOD_NAME(tmp_path: Path):
    path = tmp_path / "add_entry.json"
    assert not path.exists()
    result = dict(value=None)
    obs, obs_var, vert, model, model_var = "obs", "obs_var", "Column", "model", "model_var"
    _add_heatmap_entry_json(path, result, obs, obs_var, vert, model, model_var)
    assert path.exists()
    data = json.loads(path.read_text())
    assert data[obs_var][obs][vert][model][model_var] == result
    result.update(value=42.0)
    _add_heatmap_entry_json(path, result, obs, obs_var, vert, model, model_var)
    data = json.loads(path.read_text())
    assert data[obs_var][obs][vert][model][model_var] == result