Like the script from First Electrical Connections with a Breadboard, this script is also pre-written as a hex file with the multimeter module added.  

• Right-click measure_volts.hex and select Save link as... to download it.

measure_volts.hex

• Go to python.microbit.org.
• Click Load/Save and then drag the file you just downloaded and drop it on the gray box in the Load section.
• If the python.microbit.org editor is not connected, click the Connect button.
• Click the Flash button to load the script into the micro:bit.
• Click the Open Serial button to view the voltmeter output.
• Verify that the voltmeter displays a relatively small value, somewhere in the +/- 0.1 V range.