def __virtual__():
    supported_os_tool = {
        'FreeBSD': 'ifconfig',
        'Linux': 'brctl',
        'NetBSD': 'brconfig',
        'OpenBSD': 'ifconfig'
    }
    cur_os = __grains__['kernel']
    for _os in supported_os_tool:
        if cur_os == _os and salt.utils.which(supported_os_tool[cur_os]):
            return True
    return (False, 'The bridge execution module failed to load: requires one of the following tool/os'
        ' combinations: ifconfig on FreeBSD/OpenBSD, brctl on Linux or brconfig on NetBSD.')
Confirm this module is supported by the OS and the system has
dataset/ETHPy150Open saltstack/salt/salt/modules/bridge.py/__virtual__