def convert_compartment_id(modelseed_id, format_type):
    """ Convert a compartment ID in ModelSEED source format to another format.

    No conversion is done for unknown format types.

    Parameters
    ----------
    modelseed_id : str
        Compartment ID in ModelSEED source format
    format_type : {'modelseed', 'bigg'}
        Type of format to convert to

    Returns
    -------
    str
        ID in specified format
    """

    if format_type == 'modelseed' or format_type == 'bigg':
        return modelseed_id[0]

    return modelseed_id