code: def precision(self, idx):
      return self.positive_predictive_value(idx)
  
imports: import logging
  from collections import OrderedDict
  import numpy
  from sklearn import metrics
  from sklearn.metrics import confusion_matrix
label_desc: Use image node_id 16 for calling the ConfusionMatrix obj's underlying member method code with example usage: obj.precision(idx) and returns: self