code: def test_normalize():
      num_input = ["scalar_a", "scalar_b"]
      mean, std = _compute_normalization(TEST_DF_1, num_input)
      df = _normalize(TEST_DF_1, num_input, mean, std)
      assert np.allclose(df[num_input].mean(), 0.0)
  
file_path: lightning-flash/tests/tabular/classification/test_data.py
imports: from pathlib import Path
  from unittest.mock import Mock
  import numpy
  import pytest
  from flash.core.data.io.input import DataKeys
  from flash.core.utilities.imports import _TOPIC_TABULAR_AVAILABLE
label_desc: Use image node_id 2 for calling a global function with example usage: test_normalize() without return types