BBC Click's Jen Copestake looks at some of the week's top technology stories including:

Blockchain technology that could provide a secure way to track the legal sale of cannabis in Canada

Self-balancing electric roller skates developed by Segway-Ninebot are to be banned on UK public pavements and roads

Waymo has announced a trial where self-driving cars will ferry shoppers to and from a nearby Walmart store to pick up their groceries

See more at Click's website and @BBCClick.