code: def verify_row(self, row):
          
          param = self._parameters[row]
          if param['parameter'] == '':
              return "Auto-parameter type undefined"
          if len(param['selection']) == 0:
              return "At least one component must be selected for each auto-parameter"
          if param['parameter'] not in self._selectionParameters(param):
              return 'Parameter {} not present in all selected components'.format(param['parameter'])
          if param['parameter'] == 'filename':
              if len(param['names']) < 1:
                  return "No filenames in file auto-parameter list"
          else:
              if param['step'] == 0 and param['start'] != param['stop']:
                  return "Auto-parameter step size of 0 not allowed"
              if abs(param['stop'] - param['start']) < param['step']:
                  return "Auto-parameter step size larger than range"
              if not self.checkLimits(row, param['start']):
                  return "Auto-parameter start value invalid"
              if not self.checkLimits(row, param['stop']):
                  return "Auto-parameter stop value invalid"
          return 0
docs: Checks parameter at index *row* for invalidating conditions
  
          :returns: str -- message if error, 0 otherwise