docs: def check(self, dsm, **kwargs):
          """
          Check code clean.
  
          Args:
              dsm (:class:`DesignStructureMatrix`): the DSM to check.
  
          Returns:
              bool, str: True if code clean else False, messages
          """
          logger.debug('Entities = %s' % dsm.entities)
          messages = []
          code_clean = True
          threshold = kwargs.pop('threshold', 1)
          rows, _ = dsm.size
          for i in range(0, rows):
              if dsm.data[i][0] > threshold:
                  messages.append(
                      'Number of issues (%d) in module %s '
                      '> threshold (%d)' % (
                          dsm.data[i][0], dsm.entities[i], threshold))
                  code_clean = False
  
          return code_clean, '\n'.join(messages)