Convert a string representation of a HostHostBusAdapter into an
    object reference.

def _get_hba_type(hba_type):
    '''
    Convert a string representation of a HostHostBusAdapter into an
    object reference.
    '''
    if hba_type == "parallel":
        return vim.host.ParallelScsiHba
    elif hba_type == "block":
        return vim.host.BlockHba
    elif hba_type == "iscsi":
        return vim.host.InternetScsiHba
    elif hba_type == "fibre":
        return vim.host.FibreChannelHba

    raise ValueError('Unknown Host Bus Adapter Type')