Changes to Creates a draft contract

the items/items/quantity response's property type changed from number to string, and format from no format to number for status 200

added the new optional request property billing_address_id

added the new optional request property email_selection

added the new optional request property items/items/declared_ssp

added the new optional request property items/items/description

added the new optional request property items/items/fields

added the new optional request property purchase_order_number

added the new optional request property shipping_address_id

added the new optional request property shipping_customer_id

added the optional property approval to the response with the 200 status

added the optional property billing_address to the response with the 200 status

added the optional property email_selection to the response with the 200 status

added the optional property items/items/declared_ssp to the response with the 200 status

added the optional property items/items/description to the response with the 200 status

added the optional property items/items/fields to the response with the 200 status

added the optional property purchase_order_number to the response with the 200 status

added the optional property shipping_address to the response with the 200 status

added the optional property shipping_customer_id to the response with the 200 status