updated instructions for service client

Author: JimacoMS3

articles/iot-hub/quickstart-control-device-python.md

@@ -43,13 +43,13 @@ az extension add --name azure-cli-iot-ext
 
 If you haven't already done so, download the sample Python project from https://github.com/Azure-Samples/azure-iot-samples-python/archive/master.zip and extract the ZIP archive.
 
-For Windows, the following prerequisites are required to install the V1 IoT Hub service client Pip package:
+**For Windows**, the following prerequisites are required to install the V1 IoT Hub service client Pip package:
 
 * Make sure you have [Python version **3.6.x**](https://www.python.org/downloads/) installed.
 
 * Make sure you have the [Microsoft Visual C++ Redistributable for Visual Studio](https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads) installed.
 
-For other platforms, see the [Python Pip package distribution table](https://github.com/Azure/azure-iot-sdk-python/blob/v1-deprecated/doc/python-devbox-setup.md#python-pip-package-distribution-table) in the V1 SDK documentation. Make sure the Python 3.x version specified for your platform and any associated requirements are installed on your development machine. Installing Python 3.x rather than 2.7 enables async operations in the V2 device client, which is also used in this quickstart.
+**For non-Windows platforms**, see the [Python Pip package distribution table](https://github.com/Azure/azure-iot-sdk-python/blob/v1-deprecated/doc/python-devbox-setup.md#python-pip-package-distribution-table) in the V1 SDK documentation. Make sure the Python 3.x version specified for your platform and any associated requirements are installed on your development machine. Installing Python 3.x rather than 2.7 enables async operations in the V2 device client, which is also used in this quickstart.
 
 ## Create an IoT hub
 
@@ -160,6 +160,10 @@ The back-end application connects to a service-side endpoint on your IoT Hub. Th
 
     ![Change in simulated client](./media/quickstart-control-device-python/SimulatedDevice-2.png)
 
+    > [!NOTE]
+    > If you get an error on the import of *iothub_service_client*, make sure you've installed the exact version of Python and any other associated artifacts specified for your platform in [Prerequisites](#Prerequisites). If, after verifying the prerequisites, you still get an error, you may need to build the service client for your platform. To learn how to build the SDK for your platform, see the [devbox setup instructions](https://github.com/Azure/azure-iot-sdk-python/blob/v1-deprecated/doc/python-devbox-setup.md) in the V1 SDK documentation.
+    >
+
 ## Clean up resources
 
 [!INCLUDE [iot-hub-quickstarts-clean-up-resources](../../includes/iot-hub-quickstarts-clean-up-resources.md)]