def setPath(self, folderpath, specfiles=None):
        """Changes the folderpath of the specified specfiles. The folderpath is
        used for saving and loading of ``mrc`` files.

        :param specfiles: the name of an ms-run file or a list of names. If None
            all specfiles are selected.
        :type specfiles: None, str, [str, str]
        :param folderpath: a filedirectory
        """
        if specfiles is None:
            specfiles = [_ for _ in viewkeys(self.info)]
        else:
            specfiles = aux.toList(specfiles)

        _containerSetPath(self, folderpath, specfiles)