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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_ecmwf_macc(filename, params, startdate, stopdate, lookup_params=True, server=None, target=_ecmwf):
 """ Download data from ECMWF MACC Reanalysis API. Parameters filename : str full path of file where to save data, ``.nc`` appended if not given params : str or sequence of str keynames of parameter[s] to download startdate : datetime.datetime or datetime.date UTC date stopdate : datetime.datetime or datetime.date UTC date lookup_params : bool, default True optional flag, if ``False``, then codes are already formatted server : ecmwfapi.api.ECMWFDataServer optionally provide a server object, default is ``None`` target : callable optional function that calls ``server.retrieve`` to pass to thread Returns ------- t : thread a thread object, use it to check status by calling `t.is_alive()` Notes ----- To download data from ECMWF requires the API client and a registration key. Please read the documentation in `Access ECMWF Public Datasets <https://confluence.ecmwf.int/display/WEBAPI/Access+ECMWF+Public+Datasets>`_. Follow the instructions in step 4 and save the ECMWF registration key as `$HOME\.ecmwfapirc` or set `ECMWF_API_KEY` as the path to the key. This function returns a daemon thread that runs in the background. Exiting Python will kill this thread, however this thread will not block the main thread or other threads. This thread will terminate when the file is downloaded or if the thread raises an unhandled exception. You may submit multiple requests simultaneously to break up large downloads. You can also check the status and retrieve downloads online at http://apps.ecmwf.int/webmars/joblist/. This is useful if you kill the thread. Downloads expire after 24 hours. .. warning:: Your request may be queued online for an hour or more before it begins to download Precipitable water :math:`P_{wat}` is equivalent to the total column of water vapor (TCWV), but the units given by ECMWF MACC Reanalysis are kg/m^2 at STP (1-atm, 25-C). Divide by ten to convert to centimeters of precipitable water: .. math:: P_{wat} \\left( \\text{cm} \\right) \ = TCWV \\left( \\frac{\\text{kg}}{\\text{m}^2} \\right) \ \\frac{100 \\frac{\\text{cm}}{\\text{m}}} \ {1000 \\frac{\\text{kg}}{\\text{m}^3}} The keynames available for the ``params`` argument are given by :const:`pvlib.iotools.ecmwf_macc.PARAMS` which maps the keys to codes used in the API. The following keynames are available: ======= ========================================= keyname description ======= ========================================= tcwv total column water vapor in kg/m^2 at STP aod550 aerosol optical depth measured at 550-nm aod469 aerosol optical depth measured at 469-nm aod670 aerosol optical depth measured at 670-nm aod865 aerosol optical depth measured at 865-nm aod1240 aerosol optical depth measured at 1240-nm ======= ========================================= If ``lookup_params`` is ``False`` then ``params`` must contain the codes preformatted according to the ECMWF MACC Reanalysis API. This is useful if you want to retrieve codes that are not mapped in :const:`pvlib.iotools.ecmwf_macc.PARAMS`. Specify a custom ``target`` function to modify how the ECMWF API function ``server.retrieve`` is called. The ``target`` function must have the following signature in which the parameter definitions are similar to :func:`pvlib.iotools.get_ecmwf_macc`. :: target(server, startdate, stopdate, params, filename) -> None Examples -------- Retrieve the AOD measured at 550-nm and the total column of water vapor for November 1, 2012. True """

    if not filename.endswith('nc'):
        filename += '.nc'
    if lookup_params:
        try:
            params = '/'.join(PARAMS.get(p) for p in params)
        except TypeError:
            params = PARAMS.get(params)
    startdate = startdate.strftime('%Y-%m-%d')
    stopdate = stopdate.strftime('%Y-%m-%d')
    if not server:
        server = ECMWFDataServer()
    t = threading.Thread(target=target, daemon=True,
                         args=(server, startdate, stopdate, params, filename))
    t.start()
    return t