I've installed Peddler to connect to Marketplace Web service. 
I cannot find which is the method to list my inventory (Merchant)

```
require "peddler"

client = MWS.orders(
  primary_marketplace_id: "XXXX",
  merchant_id: "XXX",
  aws_access_key_id: "XXX",
  aws_secret_access_key: "XXXXX",
)

p client.list_inventory_supply

```

**Error**

```
app.rb:30:in `<main>': undefined method `list_inventory_supply' for #<MWS::Orders::Client:0x007fd6ab9d0f60> (NoMethodError)

```