Add or update customer
Adds a new customer if the provided email does not exist, otherwise updates the existing customer.
Add or update product
Adds a new product if the provided SKU does not exist, otherwise updates the existing product. If multiple products have the SKU, an error occurs.
Get order
Returns the order matching the specified ID. An error occurs if no matching order is found.
Update order status
Updates the status of the order with the specified ID.
