Helper to try and start machines

    @param machine:
    @type machine: IMachine
    @param session:
    @type session: ISession
    @return:
    @rtype: IProgress or None

def _start_machine(machine, session):
    '''
    Helper to try and start machines

    @param machine:
    @type machine: IMachine
    @param session:
    @type session: ISession
    @return:
    @rtype: IProgress or None
    '''
    try:
        return machine.launchVMProcess(session, '', '')
    except Exception as e:
        log.debug(e.message, exc_info=True)
        return None