def write_kw_prefs(meta_keys):
    """Write all located fcs Parameter keys to text file

    Arg:
        meta_keys: iterable of fcs metadata Parameter keys in order relative to
            location in fcs file text section.

    Returns:
        kw_prefs_filename: name of generated text file
    """
    kw_prefs_filename = 'FCS_USER_KW.txt'
    with open(kw_prefs_filename, 'w') as kw_file:
        for keyword in meta_keys:
            kw_file.write('{}\n'.format(keyword))
    return kw_prefs_filename
