code: public List<EventSubscriptionInner> listRegionalByResourceGroupForTopicType(String resourceGroupName, String location, String topicTypeName) {
          return listRegionalByResourceGroupForTopicTypeWithServiceResponseAsync(resourceGroupName, location, topicTypeName).toBlocking().single().body();
      }
docs: List all regional event subscriptions under an Azure subscription and resource group for a topic type.
  List all event subscriptions from the given location under a specific Azure subscription and resource group and topic type.
  
  @param resourceGroupName The name of the resource group within the user's subscription.
  @param location Name of the location
  @param topicTypeName Name of the topic type
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the List&lt;EventSubscriptionInner&gt; object if successful.