code: def tp(self):
      return np.sum(self.__TPmap())
  
imports: from __future__ import absolute_import, print_function
  import numpy
  from scipy import ndimage
  from niftynet.utilities.util_common import MorphologyOps, CacheFunctionOutput
label_desc: Use image node_id 15 for calling the PairwiseMeasures obj's underlying member method code with example usage: obj.tp() and returns: np