public InstagramSubscription callback(String callback) {
		Preconditions.checkValidUrl(callback, "Invalid Callback Url");

		this.params.put(Constants.CALLBACK_URL, callback);

		return this;
	}
public InstagramSubscription callback(String callback) {
		Preconditions.checkValidUrl(callback, "Invalid Callback Url");

		this.params.put(Constants.CALLBACK_URL, callback);

		return this;
	}
public InstagramSubscription callback ( String callback ) { Preconditions . checkValidUrl ( callback , "Invalid Callback Url" ) ; this . params . put ( Constants . CALLBACK_URL , callback ) ; return this ; }
Configures the callback url

@param callback The callback for your application
@return the {@link InstagramSubscription} instance for method chaining
Configures the callback url