code: def test_mse(
      data: np.ndarray, params: dict, expected: Union[float, dict, bool]
  ):
      out = mse(a=data["a"], b=data["b"])
      assert round(out, 2) == expected, "Test failed."
  
file_path: Quantus/tests/functions/test_loss_func.py
imports: from typing import Union
  import pytest
  from pytest_lazyfixture import lazy_fixture
  from quantus.functions.loss_func import *
label_desc: Use image node_id 4 for calling a global function with example usage: test_mse(data, params, expected) without return types