code: def get_X(data):
      """Return model design matrix X"""
      return data.filter(like="X").values
  
file_path: backtesting.py/doc/examples/Trading with Machine Learning.py
imports: from backtesting.test import EURUSD, SMA
  import numpy
  import pandas
  from sklearn.neighbors import KNeighborsClassifier
  from sklearn.model_selection import train_test_split
  from backtesting import Backtest, Strategy
label_desc: Use image node_id 2 for calling a global function with example usage: get_X(data) and returns: data