docs: def addSpecfile(self, specfiles, path):
          """Prepares the container for loading ``mrc`` files by adding specfile
          entries to ``self.info``. Use :func:`MsrunContainer.load()` afterwards
          to actually import the files
  
          :param specfiles: the name of an ms-run file or a list of names
          :type specfiles: str or [str, str, ...]
          :param path: filedirectory used for loading and saving ``mrc`` files
          """
          for specfile in aux.toList(specfiles):
              if specfile not in self.info:
                  self._addSpecfile(specfile, path)
              else:
                  warntext = 'Error while calling "MsrunContainer.addSpecfile()"'\
                             ': "%s" is already present "MsrunContainer.info"'\
                              % (specfile, )
                  warnings.warn(warntext)