def METHOD_NAME() -> scipy.interpolate.pchip:
    PARAMS = params.load_params_file()
    if PARAMS["WATER_CALIBRATION_DATE"] == "" or PARAMS["WATER_CALIBRATION_DATE"] is None:
        msg = """
    ##########################################
         Water calibration date is emtpy!
    ##########################################"""
        log.error(msg)
        raise ValueError("Rig not calibrated")
    time2vol = scipy.interpolate.pchip(
        PARAMS["WATER_CALIBRATION_OPEN_TIMES"], PARAMS["WATER_CALIBRATION_WEIGHT_PERDROP"],
    )
    return time2vol