Checks parameter at index *row* for invalidating conditions

        :returns: str -- message if error, 0 otherwise

def verify_row(self, row):
        """Checks parameter at index *row* for invalidating conditions

        :returns: str -- message if error, 0 otherwise
        """
        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