def valid_debugger_plugin(self, plugin):
        if (issubclass(plugin, DebuggerAdaptorPlugin) and
            hasattr(plugin, 'plugin_type')      and plugin.plugin_type == 'debugger' and
            hasattr(plugin, 'host')             and plugin.host != None):
            return True
        return False
Roll back any expired reservations.
dataset/ETHPy150Open snare/voltron/voltron/plugin.py/PluginManager.valid_debugger_plugin--crossover with--dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/db/api.py/reservation_expire