Before updating our module, we will first enable the multistore feature on our PrestaShop and create a second shop. This will permit us to test the module properly.
To enable the multistore feature, go to your PrestaShop's administration panel by navigating to Preferences | GENERAL:

Once enabled, a new menu item called Multistore will appear in the ADVANCED PARAMETERS menu:

By clicking on the Multistore option under the Advanced Parameters menu, you will get to access a section that contains the list of your shops and shop groups. At this time, you will only have one shop and one shop group. Now, we will create a new shop; click on the button named Add a new shop. The shop form will appear. Name the shop as you wish; I simply named it Second Shop
. You can leave the other fields with their default value and validate the form.