def update_longitude(inst, lon_name=None, high=180.0, low=-180.0):
    """ Update longitude to the desired range

    Parameters
    ------------
    inst : pysat.Instrument instance
        instrument object to be updated
    lon_name : string
        name of the longtiude data
    high : float
        Highest allowed longitude value (default=180.0)
    low : float
        Lowest allowed longitude value (default=-180.0)

    Returns
    ---------
    updates instrument data in column 'lon_name'

    """
    from pysat.utils.coords import adjust_cyclic_data
    if lon_name not in inst.data.keys():
        raise ValueError('uknown longitude variable name')
    new_lon = adjust_cyclic_data(inst[lon_name], high=high, low=low)
    if inst.pandas_format:
        inst[lon_name] = new_lon
    else:
        inst[lon_name].data = new_lon
    return
