code: def test_get_global_features_importance(self):
      self.test_backend.state = SmartState()
      res = self.test_backend.get_global_features_importance(
          pd.DataFrame([[-1, -2, -3, -4], [1, 2, 3, 4]]),
      )
      assert_series_equal(res, pd.Series([0.1, 0.2, 0.3, 0.4]))
  
imports: import unittest
  from unittest.mock import patch
  import types
  import numpy
  import pandas
  import category_encoders
  from sklearn.ensemble import RandomForestRegressor, RandomForestClassifier
  from pandas.testing import assert_frame_equal, assert_series_equal
  from shapash.backend.base_backend import BaseBackend, _needs_preprocessing
  from shapash.explainer.smart_state import SmartState
label_desc: Use image node_id 7 for calling the TestBaseBackend obj's underlying member method code with example usage: obj.test_get_global_features_importance() without return types