code: def extract_number(x: str):
      """Helper function to extract number from a string."""
      return float(re.findall("[0-9]+.[0-9]+", x)[0])
  
imports: import re
  from copy import deepcopy
  import matplotlib.pyplot
  import numpy
  import pandas
  import pytest
  from pytest_lazyfixture import lazy_fixture
  from sklearn.ensemble import GradientBoostingRegressor
  from sklearn.linear_model import LinearRegression
  from alibi.api.defaults import DEFAULT_DATA_PDVARIANCE, DEFAULT_META_PDVARIANCE
  from alibi.api.interfaces import Explanation
  from alibi.explainers import PartialDependence, PartialDependenceVariance, TreePartialDependence
  from alibi.explainers.pd_variance import _plot_feature_importance, _plot_feature_interaction, _plot_hbar, plot_pd_variance
label_desc: Use image node_id 20 for calling a global function with example usage: extract_number(x) and returns: float