new_contents: #!/usr/bin/env python3
  # vim:set ts=4 sts=4 sw=4 et:
  """MC Helpers.
  """
  from __future__ import division, absolute_import, print_function
  
  from km3pipe import Module
  from km3pipe.tools import zenith, azimuth, pdg2name, name2pdg
  
  
  NEUTRINOS = {'nu_e', 'anu_e', 'nu_mu', 'anu_mu', }      # noqa
  
  
  class McTruth(Module):
      """Extract MC info of 1st MC track."""
      def __init__(self, **context):
          super(self.__class__, self).__init__(**context)
  
      @classmethod
      def t2f(cls, row):
          return pdg2name(row['type'])
  
      @classmethod
      def is_nu(cls, row):
          return row['flavor'] in NEUTRINOS
  
      def process(self, blob):
          mc = blob['McTracks'].conv_to('pandas')[:, 0]
          mc['zenith'] = zenith(mc[['dir_x', 'dir_y', 'dir_z']])
          mc['azimuth'] = azimuth(mc[['dir_x', 'dir_y', 'dir_z']])
          mc['flavor'] = mc.apply(cls.t2f, axis=1)
          mc['is_neutrino'] = mc.apply(cls.is_nu, axis=1)
          blob['McTruth'] = mc
          return blob
  
subject: add MC helper module