human
Solve the following python programming problem given the following code:
@ extensions.expected_errors ((400, 404, 501)) 
@ validation.schema (hosts.update) 
def update(self, req, id, body) : 
    "Return booleanized version of body dict.

        :param Request req: The request object (containing 'nova-context'
                            env var).
        :param str id: The host name.
        :param dict body: example format {'host': {'status': 'enable',
                          'maintenance_mode': 'enable'}}
        :return: Same dict as body but 'enable' strings for 'status' and
                 'maintenance_mode' are converted into True, else False.
        :rtype: dict
        " 
    def read_enabled(orig_val) : 
        val = orig_val.strip ().lower () 
        return (val == 'enable') 
context = req.environ ['nova.context'] 
    authorize (context) 
    status = body.get ('status') 
    maint_mode = body.get ('maintenance_mode') 
    if (status is not None) : 
        status = read_enabled (status) 
if (maint_mode is not None) : 
        maint_mode = read_enabled (maint_mode) 
result = { 
        'host' : id, 
} 
    if (status is not None) : 
        result ['status'] = self._set_enabled_status (context, id, status) 
if (result is not None) : 
        result ['maintenance_mode'] = self._set_host_maintenance (context, id, maint_mode) 
return result 

    
    

    Fix the buggy line: if (result is not None) :
assistant
#Here is Python program to fix the buggy line: if (result is not None) :
.

if (maint_mode is not None) :