docs: def main(self, config_filename, file_names=None):
          """
          Loads stored routines into the current schema.
  
          :param str config_filename: The name of the configuration file of the current project
          :param list[str] file_names: The sources that must be loaded. If empty all sources (if required) will loaded.
  
          :rtype: int The status of exit.
          """
          self._io.title('Loader')
  
          if file_names:
              self.__load_list(config_filename, file_names)
          else:
              self.__load_all(config_filename)
  
          if self.error_file_names:
              self.__log_overview_errors()
              return 1
          else:
              return 0