code: public ExpressRouteGatewayInner beginCreateOrUpdate(String resourceGroupName, String expressRouteGatewayName, ExpressRouteGatewayInner putExpressRouteGatewayParameters) {
          return beginCreateOrUpdateWithServiceResponseAsync(resourceGroupName, expressRouteGatewayName, putExpressRouteGatewayParameters).toBlocking().single().body();
      }
docs: Creates or updates a ExpressRoute gateway in a specified resource group.
  
  @param resourceGroupName The name of the resource group.
  @param expressRouteGatewayName The name of the ExpressRoute gateway.
  @param putExpressRouteGatewayParameters Parameters required in an ExpressRoute gateway PUT operation.
  @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 ExpressRouteGatewayInner object if successful.