How to use the ismn.interface function in ismn

static_layers_folder = os.path.join(testdata_folder,
                                    'sat/h_saf/static_layer')

# init the ASCAT SSM reader with the paths
ascat_SSM_reader = ascat.AscatSsmCdr(ascat_data_folder, ascat_grid_folder,
                                     grid_filename='TUW_WARP5_grid_info_2_1.nc',
                                     static_layer_path=static_layers_folder)
ascat_SSM_reader.read_bulk = True


# set path to ISMN data
ismn_data_folder = os.path.join(testdata_folder,
                                 'ismn/multinetwork/header_values')

# Initialize reader
ISMN_reader = ismn.ISMN_Interface(ismn_data_folder)


i = 0

label_ascat = 'sm'
label_insitu = 'insitu_sm'

# this loops through all stations that measure soil moisture
for station in ISMN_reader.stations_that_measure('soil moisture'):
    
    # this loops through all time series of this station that measure soil moisture
    # between 0 and 0.1 meters
    for ISMN_time_series in station.data_for_variable('soil moisture', min_depth=0, max_depth=0.1):

        ascat_time_series = ascat_SSM_reader.read(ISMN_time_series.longitude,
                                                  ISMN_time_series.latitude,