code: def f1_score(tn, fp, fn, tp):
      """f1 score from confusion matrix"""
      del tn
      return 2 * tp / (2 * tp + fp + fn)
  
imports: import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: f1_score(tn, fp, fn, tp) and returns: unknown