Sending a single element in an array using XML format fails with the request being invalid

Hi,

I have an API which accepts requests using XML. It accepts an array of products. However for a case where there is only one product in the array, validation errors occur.
Sample request -
curl -X POST \ http://localhost:3000/v1/products \ -H 'cache-control: no-cache' \ -H 'content-type: application/xml' \ -d '<?xml version="1.0" encoding="UTF-8" ?> <admin> <product> <id>1</id> <price>100</price> </product> </admin>'

This is because when there is a single element in an array, the product will be parsed to a hash instead of an array of hash objects.
Expected - { admin: { products: [{ id: "1", price: "100" }] } }
Actual - { admin: { products: { id: "1", price: "100" } } }

the parameters are defined as

params do
  requires :admin, type: Hash do
    requires :products, type: Array do
      requires :id, type: String
      requires :price, type: String
    end
  end
end

Currently to overcome this, I run the following before_validation block

before_validation do
  params[:admin][:products] = [params[:admin][:products]] if params[:admin][:products].is_a?(Hash)
end

I was wondering since grape knows the request type (Array or Hash), can it convert the hash to an array before validating (similar to the before_validation block).

Notes:
Using Grape version : 1.0.0
Sample code - https://github.com/ramkumar-kr/grape-xml-error

Start with the linked grape-xml-error sample code and reproduce the single-product XML request against the shown params definition. Trace how the XML body is represented before validation and compare it with the existing before_validation workaround. Done means a single product is accepted as an array element and the request validates without that workaround.