def resolve_filenames(all_expr):
        """resolve expression for a filename

        :param all_expr:
            A comma separated list of expressions. The expressions can contain
            the wildcard characters ``*`` and ``?``. It also resolves Spark
            datasets to the paths of the individual partitions
            (i.e. ``my_data`` gets resolved to
            ``[my_data/part-00000, my_data/part-00001]``).

        :returns: A list of file names.
        :rtype: list
        """
        files = []
        for expr in all_expr.split(','):
            expr = expr.strip()
            files += fs.get_fs(expr).resolve_filenames(expr)
        log.debug('Filenames: {0}'.format(files))
        return files
resolve expression for a filename

        :param all_expr:
            A comma separated list of expressions. The expressions can contain
            the wildcard characters ``*`` and ``?``. It also resolves Spark
            datasets to the paths of the individual partitions
            (i.e. ``my_data`` gets resolved to
            ``[my_data/part-00000, my_data/part-00001]``).

        :returns: A list of file names.
        :rtype: list