code: public Observable<AccountFilterInner> updateAsync(String resourceGroupName, String accountName, String filterName, AccountFilterInner parameters) {
          return updateWithServiceResponseAsync(resourceGroupName, accountName, filterName, parameters).map(new Func1<ServiceResponse<AccountFilterInner>, AccountFilterInner>() {
              @Override
              public AccountFilterInner call(ServiceResponse<AccountFilterInner> response) {
                  return response.body();
              }
          });
      }
docs: Update an Account Filter.
  Updates an existing Account Filter in the Media Services account.
  
  @param resourceGroupName The name of the resource group within the Azure subscription.
  @param accountName The Media Services account name.
  @param filterName The Account Filter name
  @param parameters The request parameters
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the AccountFilterInner object