human
I wrote the below code

    bridges = __context__.get('lxc.bridges', None)
    if (not bridges):
        bridges = set()
        running_bridges = set()
        bridges.add(DEFAULT_BR)
        try:
            output = __salt__['cmd.run_all']('brctl    show')
            for line in output['stdout'].splitlines()[1:]:
                if (not line.startswith('    ')):
                    running_bridges.add(line.split()[0].strip())
        except (SaltInvocationError, CommandExecutionError):
            pass
        for (ifc, ip) in six.iteritems(__grains__.get('ip_interfaces', {})):
            if (ifc in running_bridges):
                bridges.add(ifc)
            elif os.path.exists('/sys/devices/virtual/net/{0}/bridge'.format(ifc)):
                bridges.add(ifc)
        bridges = list(bridges)
        def sort_bridges(a):
            pref = 'z'
            if ('lxc' in a):
                pref = 'a'
            elif ('br0' == a):
                pref = 'c'
            return '{0}_{1}'.format(pref, a)
        bridges.sort(key=sort_bridges)
        __context__['lxc.bridges'] = bridges
    return bridges

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def search_lxc_bridges():