def import_mch_metranet(filename, product, unit, accutime):
    """
    Import a 8-bit bin radar reflectivity composite from the MeteoSwiss
    archive.

    Parameters
    ----------
    filename: str
        Name of the file to import.
    product: {"AQC", "CPC", "RZC", "AZC"}
        The name of the MeteoSwiss QPE product.\n
        Currently supported prducts:

        +------+----------------------------+
        | Name |          Product           |
        +======+============================+
        | AQC  |     Acquire                |
        +------+----------------------------+
        | CPC  |     CombiPrecip            |
        +------+----------------------------+
        | RZC  |     Precip                 |
        +------+----------------------------+
        | AZC  |     RZC accumulation       |
        +------+----------------------------+

    unit: {"mm/h", "mm", "dBZ"}
        the physical unit of the data
    accutime: float
        the accumulation time in minutes of the data

    {extra_kwargs_doc}

    Returns
    -------

    out: tuple
        A three-element tuple containing the precipitation field in mm/h imported
        from a MeteoSwiss gif file and the associated quality field and metadata.
        The quality field is currently set to None.
    """
    if not METRANET_IMPORTED:
        raise MissingOptionalDependency(
            "metranet package needed for importing MeteoSwiss "
            "radar composites but it is not installed"
        )

    ret = metranet.read_file(filename, physic_value=True, verbose=False)
    precip = ret.data

    geodata = _import_mch_geodata()

    # read metranet
    metadata = geodata
    metadata["institution"] = "MeteoSwiss"
    metadata["accutime"] = accutime
    metadata["unit"] = unit
    metadata["transform"] = None
    metadata["zerovalue"] = np.nanmin(precip)
    metadata["threshold"] = _get_threshold_value(precip)
    metadata["zr_a"] = 316.0
    metadata["zr_b"] = 1.5

    return precip, None, metadata
Import a 8-bit bin radar reflectivity composite from the MeteoSwiss
archive.

Parameters
----------
filename: str
Name of the file to import.
product: {"AQC", "CPC", "RZC", "AZC"}
The name of the MeteoSwiss QPE product.\n
Currently supported prducts:

+------+----------------------------+
| Name |          Product           |
+======+============================+
| AQC  |     Acquire                |
+------+----------------------------+
| CPC  |     CombiPrecip            |
+------+----------------------------+
| RZC  |     Precip                 |
+------+----------------------------+
| AZC  |     RZC accumulation       |
+------+----------------------------+

unit: {"mm/h", "mm", "dBZ"}
the physical unit of the data
accutime: float
the accumulation time in minutes of the data

{extra_kwargs_doc}

Returns
-------

out: tuple
A three-element tuple containing the precipitation field in mm/h imported
from a MeteoSwiss gif file and the associated quality field and metadata.
The quality field is currently set to None.
pysteps/io/importers.py