import cdsapi

c = cdsapi.Client()

c.retrieve(
    'reanalysis-era5-single-levels-monthly-means',
    {
        'format': 'netcdf',
        'product_type': 'monthly_averaged_reanalysis',
        'variable': '2m_temperature',
        'year': '2020',
        'month': '12',
        'time': '00:00',
        'area': [
            60, 10, 59.5,
            10.5,
        ],
    },
    'download.nc')