code: def get_action(self, pred_line):
      separator_position = pred_line.find(",")
      return float(pred_line[:separator_position])
  
file_path: vowpal_wabbit/demo/cats/utility/ap_regression_data_join.py
imports: import sys
  import getopt
  import math
label_desc: Use image node_id 4 for calling the PredictDataJoiner_ap obj's underlying member method code with example usage: obj.get_action(pred_line) and returns: float