code: def DP_calc(TPR, TNR):
      """
      Calculate Discriminant power (DP).
  
      :param TNR: specificity or true negative rate
      :type TNR: float
      :param TPR: sensitivity, recall, hit rate, or true positive rate
      :type TPR: float
      :return: DP as float
      """
      try:
          X = TPR / (1 - TPR)
          Y = TNR / (1 - TNR)
          return (math.sqrt(3) / math.pi) * (
              math.log(X, 10) + math.log(Y, 10)
          )
      except (ZeroDivisionError, TypeError, ValueError):
          return "None"
  
imports: from __future__ import division
  import math
  from .pycm_util import normal_quantile
  from .pycm_interpret import *
  from .pycm_param import CLASS_PARAMS
label_desc: Use image node_id 29 for calling a global function with example usage: DP_calc(TPR, TNR) and returns: unknown, str