How to use the metar.Metar.Metar function in metar

def test_035_parseTime_suppress_auto_month():
    """Check that explicit month suppresses automatic month rollback."""
    next_day = tomorrow.day
    if next_day > today.day:
        last_year = today.year - 1

        timestr = "%02d1651Z" % (next_day)
        report = Metar.Metar("KEWR " + timestr, month=1)
        assert report.decode_completed
        assert report.time.day == next_day
        assert report.time.month == 1
        if today.month > 1:
            assert report.time.year == today.year
        else:
            assert report.time.year == last_year

def test_020_parseStation_legal():
    """Check parsing of the station code."""
    assert Metar.Metar("KEWR").station_id == "KEWR"
    assert Metar.Metar("METAR KEWR").station_id == "KEWR"
    assert Metar.Metar("METAR COR KEWR").station_id == "KEWR"
    assert Metar.Metar("BIX1").station_id == "BIX1"
    assert Metar.Metar("K256").station_id == "K256"

def test_020_parseStation_legal():
    """Check parsing of the station code."""
    assert Metar.Metar("KEWR").station_id == "KEWR"
    assert Metar.Metar("METAR KEWR").station_id == "KEWR"
    assert Metar.Metar("METAR COR KEWR").station_id == "KEWR"
    assert Metar.Metar("BIX1").station_id == "BIX1"
    assert Metar.Metar("K256").station_id == "K256"

def report_nowind(vis_group):
        """(Macro) Return Metar object for a report containing the given
        visibility group, without a preceeding wind group.
        """
        return Metar.Metar(sta_time + vis_group)

def report(vis_group):
        """(Macro) Return Metar object for a report given visibility group."""
        return Metar.Metar(sta_time + "09010KT " + vis_group)

def report(runway_state):
        """(Macro) Return Metar object for  given runway state group"""
        sample_metar = (
            "EGNX 191250Z VRB03KT 9999 -RASN FEW008 SCT024 " "BKN046 M01/M03 Q0989 "
        )
        return Metar.Metar(sample_metar + " " + runway_state)

def test_031_parseTime_specify_year():
    """Check that the year can be specified."""
    other_year = 2003

    report = Metar.Metar("KEWR 101651Z", year=other_year)
    assert report.decode_completed
    assert report.time.year == other_year

def report(vis_group):
        """(Macro) Return Metar object for a report with the vis group."""
        return Metar.Metar(sta_time + "09010KT " + vis_group)

def process_metar(mstr, now):
    """ Do the METAR Processing """
    mtr = None
    while mtr is None:
        try:
            mtr = Metar(mstr, now.month, now.year)
        except MetarParserError as exp:
            try:
                msg = str(exp)
            except Exception:
                return None
            if msg.find("day is out of range for month") > 0 and now.day == 1:
                now -= datetime.timedelta(days=1)
                continue
            tokens = ERROR_RE.findall(str(exp))
            orig_mstr = mstr
            if tokens:
                for token in tokens[0].split():
                    mstr = mstr.replace(" %s" % (token,), "")
                if orig_mstr == mstr:
                    print("Can't fix badly formatted metar: " + mstr)
                    return None

# try 3 times in case of download errors.
        for i in range(3):
            try:
                read_str = urllib2.urlopen(URL % stnCode).read()
                break
            except:
                _logger.info('Retry required in getWeatherObservation.')
                # wait before retrying
                time.sleep(1)

        if 'read_str' not in locals():
            # retries must have failed if there is no 'read_str' variable.
            raise Exception('Could not access %s.' % stnCode)

        obs = Metar.Metar('\n'.join( read_str.splitlines()[1:] ))  # second line onward
        _nws_cache.store(stnCode, obs)

    return obs