about homekit write data error

Problem reference title . When I send data to the device there is a problem. device is a lamp


NSNumber *num = [[NSNumber alloc]initWithInt:100];

[characteristic4 writeValue:num completionHandler:^(NSError *error){

if (error) {

NSLog(@"%@",error);

}else{

NSLog(@"send Successful");

}

}];


2015-06-10 17:25:43.235 myhome[1358:349977] Error Domain=HMErrorDomain Code=20 "Nil parameter" UserInfo=0x1758d670 {NSLocalizedDescription=Nil parameter}

about homekit write data error
 
 
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