title: no known class method for selector confusion
body: <p>I know this is a newbie question, but I am all confused. How should I call class method from another class, or shouldn't I?</p>
  
  <p>Here is my <code>ClassA</code> and <code>CoreDataHelper</code>:</p>
  
  <pre><code>#import &lt;Foundation/Foundation.h&gt;
  
  @interface ClassA : NSObject {
  
  }
  
  @property (nonatomic, retain) NSString * sessionId;
  @property (nonatomic, retain) NSString * token;
  @property (nonatomic, retain) NSString * userid;
  
  + (void) pullOfflineDataWithContext:(NSManagedObjectContext *)managedObjectContext ;
  @end
  
  
  #import "ClassA.h"
  #import "CoreDataHelper.h"
  
  @implementation ClassA
  
  
  + (void) pullOfflineDataWithContext:(NSManagedObjectContext *)managedObjectContext  {
  
      // get Contacts, Accounts, Meetings into Core Data
  
       bool asd =[CoreDataHelper insertAllObjectsForEntity:@"Contact" andContext:managedObjectContext initCoreData:jsonDict];
  
  }
  @end
  
  #import &lt;Foundation/Foundation.h&gt;
  #import &lt;CoreData/CoreData.h&gt;
  
  @interface CoreDataHelper : NSObject
  
  //For inserting objects
  +(BOOL)insertAllObjectsForEntity:(NSString*)entityName andContext:(NSManagedObjectContext *)managedObjectContext;
  
  @end
  </code></pre>