Amazon will add another six Amazon Go cashierless store concepts to its roster this year, according to reports.

While the original store took nearly a year to test before opening, the latest news signals that Amazon may have overcome any glitches experienced with its Walk Out Technology, Recode reports.

The concept allows shoppers to walk in, grab items and walk out of the store without having to go through a cashier. Machine learning algorithms and computer vision are used to track shoppers, but an inability to properly track items had previously caused the e-commerce behemoth to put its Seattle opening on hold.

The new stores will be in Seattle and Los Angeles, but it is still unclear whether they will be introduced to other markets, Recode reports.

There has been speculation that Amazon will add the concept to Whole Foods stores, and the e-commerce behemoth said the technology could be introduced to the grocery chain in the near future.