code: def _category(self):
          
  
          if self.fname.split('_')[0] == 'WAC':
              self.grid = 'WAC'
              self.img = os.path.join(self.wacpath, self.fname + '.IMG')
              self.lbl = ''
          elif self.fname.split('_')[0] == 'LDEM':
              self.grid = 'LOLA'
              self.img = os.path.join(self.lolapath, self.fname + '.IMG')
              self.lbl = os.path.join(self.lolapath, self.fname + '.LBL')
          else:
              raise ValueError("%s : This type of image is not recognized. Possible\
                               images are from %s only" % (self.fname, ', '.join(('WAC', 'LOLA'))))
docs: Type of the image: LOLA or WAC
  
          Note: Specify the attribute ``grid``, ``img`` and ``lbl`