How to use the pysat.Files function in pysat

files.loc[orig[0] + doff - pds.DateOffset(days=1)] = orig[1]
                    files = files.sort_index()
                    new_files.append(files.loc[orig[0]: orig[0] + doff - \
                            pds.DateOffset(days=1)].asfreq('D', method='pad'))
                files = pds.concat(new_files, sort = True)

                files = files.dropna()
                files = files.sort_index()
            # add the date to the filename
            files = files + '_' + files.index.strftime('%Y-%m-%d')
        return files
    elif format_str is None:
        estr = 'A directory must be passed to the loading routine for SuperMAG'
        raise ValueError(estr)
    else:
        return pysat.Files.from_os(data_path=data_path, format_str=format_str)

code = 'L1'
        desc = None
    elif level == 'level_2':
        code = 'L2'
        desc = None
    else:
        raise ValueError('Unsupported level supplied: ' + level)

    if format_str is None:
        format_str = 'ICON_'+code+'_EUV_Daytime'
        if desc is not None:
            format_str += '_' + desc + '_'
        format_str += '_{year:4d}-{month:02d}-{day:02d}'
        format_str += '_v{version:02d}r{revision:03d}.NC'

    return pysat.Files.from_os(data_path=data_path,
                               format_str=format_str)

supported_tags=supported_tags)

        fname = 'cnofs_cindi_ivm_500ms_{year:4d}{month:02d}{day:02d}_v01.cdf'
        supported_tags = {'': fname}
        list_files = functools.partial(cdw.list_files,
                                       supported_tags=supported_tags)

    """

    if data_path is not None:
        if format_str is None:
            try:
                format_str = supported_tags[sat_id][tag]
            except KeyError as estr:
                raise ValueError('Unknown sat_id or tag: ' + estr)
        out = pysat.Files.from_os(data_path=data_path,
                                  format_str=format_str)

        if (not out.empty) and fake_daily_files_from_monthly:
            out.loc[out.index[-1] + pds.DateOffset(months=1)
                    - pds.DateOffset(days=1)] = out.iloc[-1]
            out = out.asfreq('D', 'pad')
            out = out + '_' + out.index.strftime('%Y-%m-%d')
            return out

        return out
    else:
        estr = ''.join(('A directory must be passed to the loading routine ',
                        'for '))
        raise ValueError(estr)

"""

    if format_str is None:
        if tag not in list(apid.keys()):
            raise ValueError('unknown {:s} {:s} tag: {:s}'.format(platform,
                                                                  name, tag))
        if index_start_time:
            time_str = '{year:4d}{month:02d}{day:02d}_??????_????????_??????'
        else:
            time_str = '????????_??????_{year:4d}{month:02d}{day:02d}_??????'

        format_str = ''.join(('DMT_N1_{:d}_??????_'.format(apid[tag]),
                              time_str, '.DAT'))

    return pysat.Files.from_os(data_path=data_path, format_str=format_str)

code = 'L1'
        desc = None
    elif level == 'level_2':
        code = 'L2'
        desc = None
    else:
        raise ValueError('Unsupported level supplied: ' + level)

    if format_str is None:
        format_str = 'ICON_'+code+'_FUV_Daytime-ON2'
        if desc is not None:
            format_str += '_' + desc + '_'
        format_str += '_{year:4d}-{month:02d}-{day:02d}'
        format_str += '_v{version:02d}r{revision:03d}.NC'

    return pysat.Files.from_os(data_path=data_path,
                               format_str=format_str)

"""

    if format_str is None and tag is not None:
        if tag == 'north' or tag == 'south':
            hemi_fmt = ''.join(('{year:4d}{month:02d}{day:02d}.', tag,
                                '.grdex'))
            return pysat.Files.from_os(data_path=data_path,
                                       format_str=hemi_fmt)
        else:
            estr = 'Unrecognized tag name for SuperDARN, north or south.'
            raise ValueError(estr)
    elif format_str is None:
        estr = 'A tag name must be passed to SuperDARN.'
        raise ValueError(estr)
    else:
        return pysat.Files.from_os(data_path=data_path, format_str=format_str)

this routine. However, as this is a generic routine, those definitions
    can't be made here. This method could be used in an instrument specific
    module where the list_files routine in the new package defines the
    format_str based upon inputs, then calls this routine passing both
    data_path and format_str.

    Alternately, the list_files routine in methods.nasa_cdaweb may also be
    used and has more built in functionality. Supported tages and format
    strings may be defined within the new instrument module and passed as
    arguments to methods.nasa_cdaweb.list_files . For an example on using
    this routine, see pysat/instrument/cnofs_ivm.py or cnofs_vefi, cnofs_plp,
    omni_hro, timed_see, etc.

    """

    return pysat.Files.from_os(data_path=data_path, format_str=format_str)

code = 'L2'
        desc = None
    else:
        raise ValueError('Unsupported level supplied: ' + level)

    # deal with case of sat_id
    satid = sat_id.capitalize()

    if format_str is None:
        format_str = 'ICON_'+code+'_MIGHTI_Vector-Wind-'+satid
        if desc is not None:
            format_str += '_' + desc + '_'
        format_str += '_{year:4d}-{month:02d}-{day:02d}'
        format_str += '_v{version:02d}r{revision:03d}.NC'

    return pysat.Files.from_os(data_path=data_path,
                               format_str=format_str)

----
    The returned Series should not have any duplicate datetimes. If there are
    multiple versions of a file the most recent version should be kept and the
    rest discarded. This routine uses the pysat.Files.from_os constructor, thus
    the returned files are up to pysat specifications.

    Multiple data levels may be supported via the 'tag' input string.
    Multiple instruments via the sat_id string.


    """

    format_str = 'example_name_{year:04d}_{month:02d}_{day:02d}.nc'
    # we use a pysat provided function to grab list of files from the
    # local file system that match the format defined above
    return pysat.Files.from_os(data_path=data_path, format_str=format_str)

'v{version:02d}r{revision:04d}.NC'

    Note
    ----
    The returned Series should not have any duplicate datetimes. If there are
    multiple versions of a file the most recent version should be kept and the
    rest discarded. This routine uses the pysat.Files.from_os constructor, thus
    the returned files are up to pysat specifications.

    """
    
    if format_str is None:
        # default file naming
        format_str = 'tiegcm_icon_merg2.0_totTgcm.s_{day:03d}_{year:4d}.nc'
        
    return pysat.Files.from_os(data_path=data_path, format_str=format_str)