import glob


def glob_files(globname):
    """Given a list of strings to glob certain files,
        return a list of all the files

        We check that some files are alway matched to reduce the risk of input
        errors
    """
    file_list = []
    if len(globname) > 0:
        for i in range(len(globname)):
            matching_files = glob.glob(globname[i])
            if len(matching_files) == 0:
                msg =  'Could not match this file: ', globname[i]
                raise Exception(msg)
            file_list = file_list + \
                glob.glob(globname[i])

    return file_list