code: def getAnalogType(self,num):
          
          listidx = self.An.index(num)
          unit = self.uu[listidx]
  
          if unit == 'kV' or unit == 'V':
              return 'V'
          elif unit == 'A' or unit == 'kA':
              return 'I'
          else:
              print 'Unknown channel type'
              return 0
docs: Returns the type  of the channel 'num' based 
          on its unit stored in the Comtrade header file.
          
          Returns 'V' for a voltage channel and 'I' for a current channel.