code: def r2(y_pred, y_true):
      return 1 - mse(y_pred, y_true) / mse(y_true.mean(), y_true)
  
file_path: DALEX/python/dalex/dalex/model_explanations/_model_performance/utils.py
imports: import numpy
  import pandas
label_desc: Use image node_id 5 for calling a global function with example usage: r2(y_pred, y_true) and returns: unknown