I have an app that uses CoreData. I created NSManagedObjects for the two object types in CoreData. When I try to use the object and set a property on the object the compiler says "[User setUsername:]: unrecognized selector sent to instance". It doesn't matter what attribute I, [User setValue], try it always gives unrecognized?

```
User *joeBlow = [[User alloc] init];
[joeBlow setUsername:@"joeblow"];

```

OR 
 User \*joeBlow = [[User alloc] init];
 joeBlow.username = @"JoeBlow";

both give "unrecognized selector sent to instance"

Below is my code for USER:

User.h

```
@interface User : NSManagedObject

  @property (nonatomic, retain) NSString * address1;
  @property (nonatomic, retain) NSString * username;
  @property (nonatomic, retain) NSString * zip;
  @property (nonatomic, retain) NSString * email;

@end

```

User.m

```
@implementation User

  @dynamic address1;
  @dynamic username;
  @dynamic zip;
  @dynamic email;

@end

```