new_contents: import numpy as np
  import re
  
  def extract_train():
      return extract('dataset/train.txt')
  
  def extract_test():
      return extract('dataset/test.txt')
  
  def extract(file):
      input_file = open(file)
      traindata = input_file.readlines()
      features = []
      targets = []
  
      for line in traindata:
          formatted_line = line.replace("\n", "")
          target_i = formatted_line.split(" ")[1]
          feature_i = re.sub(r"(\d+):", "", formatted_line).split(" ")[2:]
  
          targets.append(target_i)
          features.append(feature_i)
  
      return (np.array(features).astype(np.float), np.array(targets).astype(np.int))
subject: Implement feature extractor from data set files