text: #import <Foundation/Foundation.h>
  #import "../Model/Earthquake.h"
  #import "EarthquakeDelegate.h"
  
  NS_ASSUME_NONNULL_BEGIN
  
  /// Earthquake Service protocol - delegates can register for new earthquake
  /// data once it's ready.
  @protocol EarthquakeServiceProtocol <NSObject>
  
  /// Adds a new EarthquakeDelegate instance.
  -(void) addListener: (id<EarthquakeDelegate>) listener;
  
  /// Stop a registerede EarthquakeDelegate instance from receiving further
  /// earthquake events.
  -(void) removeListener: (id<EarthquakeDelegate>) listener;
  
  @end
  
  NS_ASSUME_NONNULL_END
  