code: public SubscriptionResponse createSubscription() throws InstagramException {
  		String callback = params.get(Constants.CALLBACK_URL);
  		if(callback == null){
  			callback = "";
  		}
  		Preconditions.checkEmptyString(callback, "You must provide a callback url");
  
          final OAuthRequest request = prepareOAuthRequest(Verbs.POST);
  		request.addBodyParameter(Constants.ASPECT, "media");
  		
  		for(Map.Entry<String, String> entry: this.params.entrySet()){
  			request.addBodyParameter(entry.getKey(), entry.getValue());
  		}
  
          try {
              final Response response = request.send();
              return getSubscriptionResponse(response.getBody());
          } catch (IOException e) {
              throw new InstagramException("Failed to create subscription", e);
          }
  	}
docs: Creates a subscription with the current state of this instance.
  <p/>
  The {@link SubscriptionResponse} holds the result of the subscription such as the identifier
  of the subscription that can be used later to {@linkplain #deleteSubscription(String) delete it}.
  
  @return the result of the subscription
  @throws InstagramException