docs: def build_data(self, plugin, attribute, stat):
          """Build and return the data line"""
          line = ''
  
          if attribute is not None:
              line += '{}{}'.format(str(stat.get(attribute, self.na)),
                                    self.separator)
          else:
              if isinstance(stat, dict):
                  for v in stat.values():
                      line += '{}{}'.format(str(v), self.separator)
              elif isinstance(stat, list):
                  for i in stat:
                      if isinstance(i, dict) and 'key' in i:
                          for v in i.values():
                              line += '{}{}'.format(str(v), self.separator)
              else:
                  line += '{}{}'.format(str(stat), self.separator)
  
          return line