def __virtual__():
    # Disable on these platforms, specific service modules exist:
    if salt.utils.systemd.booted(__context__):
        return (False, 'The upstart execution module failed to load: this system was booted with systemd.')
    elif __grains__['os'] in ('Ubuntu', 'Linaro', 'elementary OS', 'Mint'):
        return __virtualname__
    elif __grains__['os'] in ('Debian', 'Raspbian'):
        debian_initctl = '/sbin/initctl'
        if os.path.isfile(debian_initctl):
            initctl_version = salt.modules.cmdmod._run_quiet(debian_initctl + ' version')
            if 'upstart' in initctl_version:
                return __virtualname__
    return (False, 'The upstart execution module failed to load: '
        ' the system must be Ubuntu-based, or Debian-based with upstart support.')
Invoke a callable on the next cycle of the main event loop
dataset/ETHPy150Open saltstack/salt/salt/modules/upstart.py/__virtual__--crossover with--dataset/ETHPy150Open nucleic/enaml/enaml/qt/qt_application.py/QtApplication.deferred_call