docs: def Fierz_to_JMS_nunu(C, ddll):
      """From Fierz to semileptonic JMS basis for Class V.
      `ddll` should be of the form 'sbl_enu_tau', 'dbl_munu_e' etc."""
      s = str(dflav[ddll[0]] + 1)
      b = str(dflav[ddll[1]] + 1)
      l = str(lflav[ddll[4:ddll.find('n')]] + 1)
      lp = str(lflav[ddll[ddll.find('_',5)+1:len(ddll)]] + 1)
      ind = ddll.replace('l_','').replace('nu_','')
      d = {
          "VnudLL" + '_' + l + lp + s + b : C['F' + ind + 'nu'],
          "VnudLR" + '_' + l + lp + s + b : C['F' + ind + 'nup']
      }
      return symmetrize_JMS_dict(d)